Sindh Mdcat Reconduct 2024 — Solved Past Paper with Answers

Q1. Choose the correct set of prepositions to complete the given sentence:Since she believed _ her abilities, she didn't ask _ any help.

• A. In, for✓
• B. With, about
• C. At, for
• D. On, for

Explanation: The correct phrase is "believe in" when referring to trust or confidence in someone or something & "ask for" is used in terms of requesting, hence it fits best.

Q2. Choose the sentence with the correct use of the comparative degree of an adjective:

• A. My bed is more big than my desk.
• B. My bed is bigger then my desk.
• C. My bed is bigger than my desk.✓
• D. My bed is more bigger than my desk.

Explanation: Correct: "Bigger than" is the correct comparative structure.

Q3. Choose the word closest in meaning to the underlined phrase in the sentence:The firemen took several hours to put out the fire.

• A. Dislocate
• B. Extinguish✓
• C. Producer
• D. Broadcast

Explanation: "Put out" means to extinguish a fire, making "extinguish" the correct answer.

Q4. Punctuate the following sentence correctly:

• A. There was heavy fog in the morning the services at the airport were closed.
• B. There was heavy fog in the morning, the services at the airport were closed
• C. There was heavy fog in the morning; the services at the airport were closed.✓
• D. There was heavy fog in the morning: the services at the airport were closed.

Explanation: A semicolon is correctly used to join two closely related independent clauses.

Q5. Identify the correct spelling of the given word:

• A. Greivous
• B. Grevuous
• C. Grievous✓
• D. Griveous

Explanation: "Grievous" is the correct spelling, meaning serious or severe.

Q6. Complete the given sentence with the most appropriate pronoun: Scientists _ are turning away from the cruder mechanical ideas.

• A. Ourselves
• B. Herself
• C. Themselves✓
• D. Theirselves

Explanation: "Themselves" is the correct reflexive pronoun for "scientists" which is plural.

Q7. Identify the tense of the given sentence:The sick child has been sleeping for three hours

• A. Present Perfect Continuous Tense✓
• B. Present Perfect Tense
• C. Past Perfect Tense
• D. Present Continuous Tense

Explanation: The sentence uses "has been sleeping", which is the Present Perfect Continuous tense, indicating an action that started in the past and is still continuing.

Q8. Choose the correct option.

• A. After several days of discussion, the committee agreed to the amount of money to donate.
• B. After several days of discussion, the committee agreed at the amount of money to donate
• C. After several days of discussion, the committee agreed with the amount of money to donate.
• D. After several days of discussion, the committee agreed on the amount of money to donate.✓

Explanation: "Agreed on" is the correct phrase when referring to a decision or an amount.

Q9. Choose the correct option:

• A. I now feel sadly and inadequately that I don’t have enough money to buy the books I want.
• B. I now feel sad and inadequate that I don’t have enough money to buy the books I want.✓
• C. I now feel sad and inadequate that I don’t have money enough to buy the books I want.
• D. I now feel sad and inadequate that I have not enough money buying the books I want.

Explanation: The "sad" And "inadequate" are adjectives and grammatically correct and follows proper word order. The infinitive “to buy the books I want” clearly shows the purpose of needing money.

Q10. Find the error:The judges on the panel declared that of the two singers, John’s song was more melodious.

• A. On
• B. Of the two
• C. John’s song
• D. More melodious✓

Explanation: The correct phrase should be 'the more melodious' when comparing two singers. The definite article 'the' is necessary to indicate a specific comparison between John’s song and the other singer's song. Without it, the phrase is grammatically incomplete. The other options are correct in their usage, but they do not address the primary error in the sentence, which lies in the comparative structure.

Q11. CD4 receptor site is found in all types of cells except:

• A. Helper T cells
• B. MHCH
• C. Brain cells✓
• D. Suppressor T cells

Explanation: Brain cells – Correct. CD4 receptors are not present on brain cells as they are not part of the immune system.

Q12. A Russian scientist discovered that certain diseases could be transmitted by an agent that could pass through a very fine filter, which is called:

• A. Bacteria
• B. Fungi
• C. Algae
• D. Viruses✓

Explanation: Dmitri Ivanovsky discovered that viruses could pass through filters that trapped bacteria, leading to the discovery of these infectious agents.

Q13. Examples of reverse transcribing diploid single-stranded RNA viruses are:

• A. Hepatitis B
• B. HIV✓
• C. Rabies
• D. Chicken Pox

Explanation: HIV (Human Immunodeficiency Virus) is a retrovirus that has diploid single-stranded RNA and uses reverse transcription.

Q14. Viruses are called non-cellular infectious entities because:

• A. They are pathogens and cause infections
• B. They can replicate inside as well as outside the living cells
• C. They cause infections and can only replicate inside living cells✓
• D. They have a capsid to infect the host

Explanation: They cause infections and can only replicate inside living cells – Correct. Viruses are obligate intracellular parasites, meaning they need a host cell to reproduce.

Q15. Which statement is correct about the glycolysis process?

• A. 2 ATP are produced and 2 ATP are consumed
• B. 1 ATP is produced and 2 ATP are consumed
• C. 2 ATP are produced and 1 ATP is consumed
• D. 4 ATP are produced and 2 ATP are consumed✓

Explanation: 4 ATP are produced and 2 ATP are consumed – Correct. Glycolysis generates 4 ATP molecules but consumes 2, leading to a net gain of 2 ATP.

Q16. During the light-dependent phase of photosynthesis, the water molecule is broken down into:

• A. 2H, 2e and 1/2 O₂✓
• B. 4H, 4e and 2 O₂
• C. 2H, 2e and 2 O₂
• D. 4H, 2e and 4 O₂

Explanation: 2H, 2e and 1/2 O₂ – Correct. Photolysis of water during photosynthesis produces 2 protons (H⁺), 2 electrons (e⁻), and ½ molecule of oxygen (O₂) per water molecule.

Q17. ATP is best defined as:

• A. The molecule that has no role in muscle contraction
• B. The molecule that releases energy when a phosphate molecule is added
• C. The molecule that is only present inside the nucleus
• D. The molecule that releases energy when the phosphate molecule is removed✓

Explanation: The molecule that releases energy when the phosphate molecule is removed – Correct. ATP releases energy when hydrolyzed to ADP by removing a phosphate group.

Q18. Erythrose is a type of monosaccharide that is commonly known as:

• A. Triose
• B. Tetrose✓
• C. Pentose
• D. Heptose

Explanation: Tetrose is the correct choice because erythrose contains four carbon atoms. Sugars with four carbons fall into the tetrose category, so erythrose fits this group.

Q19. The hypothalamus regulates the signaling molecule like

• A. Granzyme
• B. Spermine
• C. Pyrogen✓
• D. Prostaglandin

Explanation: Pyrogen – Correct. Pyrogens are signaling molecules that induce fever and are regulated by the hypothalamus.

Q20. In the electron transport chain, the ultimate electron acceptor is:

• A. NADH
• B. None of these
• C. Oxygen✓
• D. Cytochrome complex

Explanation: Oxygen – Correct. Oxygen acts as the final electron acceptor in the electron transport chain, forming water.

Q21. The following are viral diseases except:

• A. Hepatitis
• B. Polio
• C. Syphilis✓
• D. AIDS

Explanation: Syphilis is caused by the bacterium Treponema pallidum, not a virus.It spreads mainly through sexual contact and can progress through several stages if untreated.

Q22. The property of water that is important to biological membrane stability is:

• A. Anomalous
• B. Amphoteric
• C. Hydrophobic exclusion✓
• D. Hydrophobic inclusion

Explanation: Hydrophobic exclusion – Correct. This property helps maintain the integrity of biological membranes by preventing the mixing of hydrophobic and hydrophilic components.

Q23. The glycosidic linkage between glucose and fructose is:

• A. Alpha-1, Beta-2✓
• B. Alpha-1, Beta-4
• C. Alpha-1, Alpha-4
• D. Beta-1,4

Explanation: Alpha-1, Beta-2 – Correct. Sucrose, formed by glucose and fructose, has an alpha-1, beta-2 glycosidic bond.

Q24. Cyclic phosphorylation is stimulated by:

• A. Low level of NADPH
• B. High level of NADPH✓
• C. Low light intensity
• D. High light intensity

Explanation: Cyclic phosphorylation is a process that occurs in the light-dependent reactions of photosynthesis, where electrons are recycled within the photosystem to generate ATP without producing NADPH. It is stimulated by a high level of NADPH because this indicates that the cell has sufficient reducing agents and needs more ATP to maintain balance in the energy supply. Therefore, when NADPH levels are high, the demand for ATP increases, leading to the activation of cyclic phosphorylation. The other options are incorrect because:Low level of NADPH would not stimulate cyclic phosphorylation as it indicates a shortage of reducing power needed for other processes.Low light intensity affects the overall efficiency of photosynthesis but does not specifically trigger cyclic phosphorylation.High light intensity could lead to increased overall activity but does not directly correlate with the stimulation of cyclic phosphorylation as it depends more on the ATP/NADPH ratio than light intensity alone.

Q25. A process by which one glycerol molecule is linked with three fatty acids by the esterification molecule is known as:

• A. Acylglycerol✓
• B. Wax
• C. Cholesterol
• D. Phospholipids

Explanation: Acylglycerol is correct because triacylglycerols are made when glycerol reacts with three fatty acids to form ester bonds. This esterification produces the triglycerides that serve as the main storage form of fats in the body.

Q26. The layer of the plant cell wall formed at the time of cytokinesis is

• A. Primary wall
• B. Secondary wall
• C. Middle lamella✓
• D. Tertiary wall

Explanation: The correct answer is the middle lamella, which is the layer that forms during cytokinesis, serving to bond adjacent plant cells together. This layer is rich in pectin and acts as a glue-like substance that helps maintain the integrity of plant tissue. The primary wall is established earlier during the cell's growth phase, providing initial structure but does not form at the time of cytokinesis. The secondary wall develops later, once the cell has ceased expanding, to provide further strength. Meanwhile, the tertiary wall is a specialized layer found in certain cells and does not relate to the cytokinesis process.

Q27. Cell membrane is selectively permeable due to:

• A. Proteins✓
• B. Cholesterol
• C. Phospholipids
• D. Enzymes

Explanation: The correct answer is Proteins, as they are essential for the selective permeability of the cell membrane. Embedded proteins act as channels or carriers that facilitate the movement of specific molecules in and out of the cell, thereby regulating its internal environment. While phospholipids create the structure of the membrane and cholesterol aids in fluidity, they do not selectively allow substances to pass. Enzymes, while crucial for metabolic processes, do not play a role in determining what can cross the cell membrane. Therefore, understanding the role of proteins is key to grasping how the cell membrane maintains its selective permeability.

Q28. During photorespiration, an acid glycolate is formed, which is converted into glycine by:

• A. Lysosomes
• B. Golgi complex
• C. Peroxisome✓
• D. Vacuole

Explanation: Peroxisome – Correct. Peroxisomes process glycolate into glycine during photorespiration.

Q29. The pulmonary volume is an essential part of pulmonary ventilation. It depends upon the:

• A. Physical activity✓
• B. Body volume
• C. Body composition
• D. Composition of air

Explanation: Physical activity – Correct. Pulmonary volume changes depending on physical activity; increased exertion requires higher lung ventilation.

Q30. The human brain is different from an animal's brain due to:

• A. The cerebral cortex of the animal's brain is more developed
• B. The cerebral cortex is absent in the human brain
• C. Cerebral cortex is absent in all animals' brains
• D. The cerebral cortex of the human brain is more developed✓

Explanation: The cerebral cortex of the human brain is more developed – Correct. Humans have a highly developed cerebral cortex, responsible for advanced cognitive abilities like reasoning, language, and problem-solving.

Q31. Who receives stimuli and conducts impulses to the cell body?

• A. Axon
• B. Dendrites✓
• C. Motor neurons
• D. Sensory neuron

Explanation: Dendrites – Correct. Dendrites receive stimuli from the environment or other neurons and conduct impulses to the cell body.

Q32. A nerve impulse arriving at the axon terminal causes the opening of:

• A. Calcium channel✓
• B. Potassium channel
• C. Calcium & sodium channels
• D. Chloride channel

Explanation: Calcium channel – Correct. When an impulse reaches the axon terminal, voltage-gated calcium channels open, allowing Ca²⁺ to enter and trigger neurotransmitter release.

Q33. The first stable product of the light-independent reaction having 3-carbons is:

• A. 3-phosphoglyceraldehyde
• B. 3-phosphoglyceric acid✓
• C. 1,3-biphosphate glycerate
• D. Dihydroxyacetone phosphate

Explanation: 3-phosphoglyceric acid – Correct. This is the first stable 3-carbon compound formed in the Calvin cycle.

Q34. A disulfide bridge is found in which biomolecule?

• A. Enzyme
• B. Carbohydrate
• C. Protein✓
• D. Lipid

Explanation: Protein is correct because disulfide bonds form between cysteine residues and help stabilize a protein’s shape. These covalent links hold parts of the polypeptide together and strengthen the overall structure.

Q35. The number of spinal nerves that originate from the spinal cord:

• A. 24 nerves
• B. 40 nerves
• C. 48 nerves
• D. 62 nerves✓

Explanation: Spinal nerves are 31 pairs (62 total) of mixed nerves in the peripheral nervous system that connect the spinal cord to the rest of the body, carrying motor, sensory, and autonomic signals. They are grouped into five regions: eight cervical, 12 thoracic, five lumbar, five sacral, and one coccygeal pair. Each nerve has a dorsal root (sensory) and a ventral root (motor) that merge to form a mixed nerve trunk.

Q36. Which of the following helps in long-term memory in humans?

• A. Cerebrum
• B. Medulla
• C. Cerebellum
• D. Hippocampus✓

Explanation: The hippocampus is a complex brain structure, curved like a seahorse, located deep in the temporal lobe, that is critical for learning and memory, especially for converting short-term memories into long-term ones.

Q37. The pathway in which water & minerals are stopped by a Casparian strip is known as

• A. Amygdala
• B. Cerebellum
• C. Motor cortex
• D. Occipital lobe
• E. None of the given options✓

Explanation: None of the given options correctly refer to the Casparian strip, which is a structure in plant roots that regulates water and mineral uptake

Q38. Nicotine stimulates heart rate, blood pressure, and muscular activity because:

• A. It has excitatory effects on acetylcholine receptors✓
• B. It has inhibitory effects on acetylcholine receptors
• C. It inhibits the synapse between neurons
• D. Causing drop in the heart rate

Explanation: It has excitatory effects on acetylcholine receptors – Correct. Nicotine binds to nicotinic acetylcholine receptors, stimulating the nervous system and increasing heart rate and blood pressure.

Q39. _Completes the life cycle in two boats snail, sheep, or man

• A. Liver Fluke✓
• B. Snail
• C. Earthworm
• D. Tapeworm

Explanation: Liver Fluke – Correct. The liver fluke (Fasciola) has a complex life cycle involving snails and mammals (e.g., sheep or humans) as hosts.

Q40. Which statement is correct about cnidarians?

• A. They kill the prey with the help of stinging cells✓
• B. They kill the prey with the help of tentacles
• C. They kill the prey with the help of spicules
• D. They kill the prey with the help of barbs

Explanation: They kill the prey with the help of stinging cells – Correct. Cnidarians have specialized stinging cells (nematocysts) in their tentacles that help immobilize prey.

Q41. What are the true characteristics of class Anthozoa?

• A. Mesoglea fibrous, predominantly medusoid
• B. Mesoglea cellular, both polyp & medusa
• C. Mesoglea fibrous, polypoid forms only✓
• D. Mesoglea, non-cellular, polypoids form

Explanation: Mesoglea fibrous, polypoid forms only – Correct. Class Anthozoa includes organisms such as corals and sea anemones, which exist only in the polyp stage.

Q42. Common characteristics of Hirudinaria are:1. Setae & parapodia absent 2. Setae are present but parapodia absent 3. Blood suckers are present

• A. 1, 2 & 3
• B. 1 & 3✓
• C. 1 & 2
• D. 2 & 3

Explanation: 1 & 3 – Correct. Hirudinaria (a genus of leeches) lacks setae and parapodia and is a blood-sucking annelid.

Q43. The flatworm that is the endoparasite of humans:

• A. Dugesia
• B. Fasciola
• C. Taenia✓
• D. Hydra

Explanation: Taenia – Correct. Taenia (tapeworm) is an endoparasite that resides in the human intestines.

Q44. Which statement about enzymes is essential to the lock & key hypothesis?

• A. Enzyme molecules each have a distinct shape✓
• B. Enzyme molecules are catalysts
• C. Enzyme molecules can be damaged by high temperature
• D. Enzyme molecules can be damaged by high pH value

Explanation: Enzyme molecules each have a distinct shape – Correct. The lock and key hypothesis states that enzymes have specific active sites complementary to their substrates.

Q45. The oxygen transported through blood plasma is about:

• A. 1%
• B. 3%✓
• C. 5%
• D. 7%

Explanation: 3% – Correct. Around 3% of oxygen is dissolved in plasma, while the majority is bound to hemoglobin in red blood cells.

Q46. Penicillin is a kind of antibiotic that works as

• A. Resistor
• B. Uncompetitive inhibitor
• C. Non-competitive inhibitor
• D. Competitive inhibitor✓

Explanation: Penicillin is classified as a competitive inhibitor because it competes with the substrate for binding to the active site of the bacterial enzyme transpeptidase, which is crucial for cell wall synthesis. By occupying the active site, penicillin prevents the substrate from binding, effectively inhibiting the enzyme's activity and leading to the death of the bacteria.The other options are incorrect for the following reasons:Resistor: This term is not related to enzyme kinetics or inhibition and thus does not apply.Uncompetitive inhibitor: This type of inhibitor only binds to the enzyme-substrate complex, which does not represent how penicillin functions.Non-competitive inhibitor: Non-competitive inhibitors can bind to both the free enzyme and the enzyme-substrate complex, but penicillin specifically competes for the active site, which is characteristic of competitive inhibition.

Q47. All of the following are examples of polysynaptic transmissions except:

• A. Heartbeat
• B. Breathing
• C. Knee jerk✓
• D. Playing games

Explanation: The knee-jerk reflex, also known as the patellar reflex, is an involuntary and rapid kick of the lower leg in response to a tap on the patellar tendon. This stretch reflex is initiated by sensory neurons that detect the stretch in the quadriceps muscle, sending a signal to the spinal cord, which then sends a signal back to the muscle to contract and cause the leg to extend. The reflex is a monosynaptic reflex arc, meaning it involves a direct connection between a sensory and a motor neuron and occurs without brain involvement.

Q48. The cells which do not secrete/stimulate antibodies:

• A. T lymphocytes✓
• B. B lymphocytes
• C. T Helper cells
• D. None of these

Explanation: T lymphocytes – Correct. T cells do not produce antibodies; instead, they help regulate immune responses.

Q49. Use & disuse of the postulate of organs was given by:

• A. Darwin
• B. Wallace
• C. Weismann
• D. Lamarck✓

Explanation: Lamarck – Correct. Lamarck's theory of evolution suggested that organs develop or diminish based on their usage.

Q50. All the living entities are created by God, the theory named as:

• A. Theory of natural selection
• B. Theory of survival of fittest
• C. Theory of inheritance of acquired characters
• D. Theory of special creation✓

Explanation: Theory of special creation – Correct. This theory states that all living beings were created by a divine power.The theory of special creation is a theological doctrine stating that the universe and all life were created in their current forms by a divine power, or God. This view posits that species were created individually and are not related to one another through evolution, but rather through a supernatural event. It is a religious belief, not a scientific one, and is contradicted by scientific evidence like the fossil record and genetic studies.

Q51. Choose the correct flow of impulse transmission in the human heart:

• A. AV node - SA node - Bundle of His - Purkinje fibers
• B. SA node - AV node - Bundle of His - Purkinje fibers✓
• C. SA node - AV node - Purkinje fibers - Bundle of His
• D. AV node - SA node - Purkinje fibers - Bundle of His

Explanation: SA node - AV node - Bundle of His - Purkinje fibers – Correct. The correct conduction pathway is: SA node → AV node → Bundle of His → Purkinje fibers.

Q52. A bone that lies in between the skull & postcranial skeleton is:

• A. Hyoid bone✓
• B. Incus bone
• C. Malleus bone
• D. Stapes bone

Explanation: Hyoid bone – Correct. The hyoid bone is located in the throat region and serves as a connection between the skull and the postcranial skeleton.

Q53. Which of the following is not a non-specific immune response?

• A. HCl
• B. T Cells✓
• C. Mucus
• D. Spermine

Explanation: T Cells – Correct. T cells are part of the adaptive immune system, providing specific immunity, not non-specific immunity.

Q54. The system that returns lost blood back from the body to the circulatory system is:

• A. Lymphatic system✓
• B. Digestive system
• C. Cardiovascular system
• D. Immune system

Explanation: Lymphatic system – Correct. The lymphatic system collects excess interstitial fluid and returns it to the bloodstream, preventing fluid accumulation.

Q55. The most abundant type of WBC that reach rapidly at the site of infection are:

• A. Neutrophils✓
• B. Macrophages
• C. Basophils
• D. Lymphocytes

Explanation: Neutrophils – Correct. Neutrophils are the most abundant white blood cells and are the first responders to infections.

Q56. The example of carnivorous plants is:

• A. Funaria
• B. Polypodium glycyrrhiza
• C. Pinus
• D. Dionaea muscipula✓

Explanation: Dionaea muscipula – Correct. Also known as the Venus flytrap, this plant captures and digests insects. Dionaea muscipula is the scientific name for the Venus flytrap, a famous carnivorous plant known for its unique, bivalve-like traps that snap shut to capture and digest insects.

Q57. The Casparian strip is present in:

• A. Epidermis layer
• B. Endodermis layer✓
• C. Xylem layer
• D. Phloem layer

Explanation: Endodermis layer – Correct. The Casparian strip is a waterproof barrier in the endodermis that controls water and nutrient flow into the vascular system.

Q58. The thoracic cavity is separated from the abdominal region by:

• A. Peritoneum membrane
• B. Mucous membrane
• C. Diaphragm✓
• D. Mediastinum

Explanation: Diaphragm – Correct. The diaphragm is a muscular partition that separates the thoracic and abdominal cavities.

Q59. The boiling point of water in the Kelvin scale is:

• A. 0 K
• B. 273 K
• C. 32 K
• D. 373 K✓

Explanation: 373 K – Correct. Water boils at 100°C, which equals 373 K.

Q60. Atomic Mass Unit (AMU) is equal to:

• A. Mass of one atom of H
• B. Equal to the mass of an electron
• C. 1.66 × 10-27 kg✓
• D. 1.66 × 10⁻²⁸ g

Explanation: The correct answer is 1.66 × 10-27 kg, which represents the mass of one atomic mass unit (AMU). This unit is used to express the mass of atomic and subatomic particles. 1 AMU is defined as one twelfth of the mass of an unbound neutral atom of carbon-12, and it is approximately equal to the mass of a proton or neutron. The other options are incorrect for the following reasons:Mass of one atom of H: While hydrogen's mass is close to 1 AMU, this option does not accurately reflect the definition of AMU, which is based on carbon-12.Equal to the mass of an electron: The mass of an electron is much smaller than that of protons and neutrons, and thus does not represent the AMU.1.66 × 10⁻²⁸ g: Although this numerical value is close, it is incorrect because AMU is conventionally expressed in kilograms, and the correct value is 1.66 × 10⁻²⁴ kg.

Q61. The average distance covered by the gas molecule between successive collisions is known as:

• A. Free path
• B. Mean free path✓
• C. Total free path
• D. Total path

Explanation: Mean free path – Correct. The mean free path is the average distance a gas molecule travels before colliding with another molecule.

Q62. The gas law in which the pressure is kept constant is known as:

• A. Boyle’s Law
• B. Charles’s Law✓
• C. Dalton’s Law
• D. Graham’s Law

Explanation: Charles’s Law – Correct. Charles’s Law states that at constant pressure, the volume of a gas is directly proportional to its temperature (V/T = constant).

Q63. The pressure 14.7 psi is equal to:

• A. 1 torr
• B. 1 pascal
• C. 1 atm✓
• D. 1 Nm

Explanation: 1 atm – Correct. 14.7 psi is equivalent to 1 atm (atmosphere) of pressure.

Q64. A magnetic field exerts a force on a charged particle:

• A. If the particle is moving across the field lines✓
• B. If the particle is moving along the field lines
• C. If the particle is at rest
• D. Always experiences force

Explanation: If the particle is moving across the field lines – Correct. A charged particle moving perpendicular to the field lines experiences a Lorentz force, given by F = q(v × B).

Q65. When the magnetic field and area vector are perpendicular, the magnetic flux will be

• A. Zero✓
• B. Minimum
• C. Maximum
• D. Optimum

Explanation: Zero – Correct. Magnetic flux is given by Φ = B A cos(θ), and when θ = 90°, cos(90°) = 0, so the flux is zero.

Q66. A coil of 600 turns is threaded by a magnetic flux of 8 webers. If this flux is reduced to 5 webers in 3 seconds, the induced EMF in the coil will be:

• A. 600V✓
• B. 700V
• C. 800V
• D. 900V

Explanation: 600V – Correct. The correct induced EMF calculated is 600V. Using Faraday’s Law:E=−N ΔΦ​/ΔtE=−600×(5−8)​/3E=−600×−3/3 ​=600V

Q67. A generator supplies 100V to the primary coil of a transformer. The primary has 150 turns, and the secondary has 500 turns. The secondary voltage is:

• A. 700V
• B. 333V✓
• C. 900V
• D. 1000V

Explanation: Using the transformer formula:Vs/Vp​​​=Ns/​​NpVs​=Vp​×Ns​​/Np​Vs​=100×500/​150Vs​=100×3.33=333V

Q68. The force responsible for binding the nucleus is:

• A. Coulomb's force
• B. Newton force
• C. Weak Nuclear force
• D. Strong Nuclear force✓

Explanation: Strong Nuclear force – Correct: This is the fundamental force that holds protons and neutrons together in the nucleus, overcoming the repulsive Coulomb force between protons.

Q69. When two negative beta particles are emitted from a nucleus, then the mass number:

• A. No change✓
• B. Increases by 1
• C. Increases by 2
• D. Increases by 3

Explanation: No change – Correct: Beta decay occurs when a neutron converts into a proton and an electron (beta particle). While the atomic number increases by 1 per beta emission, the mass number remains unchanged since a neutron is simply replaced by a proton. Emitting two beta particles means two neutrons have turned into protons, but the total nucleon count (mass number) stays the same.

Q70. A 40g radioactive material is placed in a chamber, having a half-life of 20 days. How much will be left after 80 days:

• A. 40gm
• B. 20gm
• C. 5gm
• D. 2.5gm✓

Explanation: Correct. Here's the calculation:Calculate the number of half-lives:Total time elapsed = 80 daysHalf-life = 20 daysNumber of half-lives = 80 days / 20 days = 4 half-livesCalculate the remaining mass:After 1 half-life: 40g / 2 = 20gAfter 2 half-lives: 20g / 2 = 10gAfter 3 half-lives: 10g / 2 = 5gAfter 4 half-lives: 5g / 2 = 2.5gTherefore, 2.5g of the radioactive material will be left after 80 days.

Q71. Which of the following electromagnetic radiation has the highest penetrating power?

• A. Alpha rays
• B. Beta rays
• C. Gamma rays✓
• D. Proton rays

Explanation: Gamma rays – Correct: Gamma rays are highly penetrating and require thick lead or concrete shielding to stop them.

Q72. The skin cancer can be caused by :

• A. Alpha radiation
• B. Beta radiation
• C. Gamma radiation
• D. Ultraviolet radiation✓

Explanation: Ultraviolet radiation – Correct: UV radiation from the sun or artificial sources is the main cause of skin cancer, as it can directly damage DNA in skin cells.

Q73. The speed of light in the vacuum is the same for all observers regardless of their relative motion or the motion of the source of the light", is the important postulate of:

• A. Special conductivity
• B. Special resistivity
• C. Special theory of relativity✓
• D. General theory of relativity

Explanation: Special theory of relativity – Correct: Einstein’s special theory of relativity states that the speed of light is constant for all observers, regardless of their motion or the motion of the source.

Q74. The process of converting an alternating current waveform into a direct current waveform is referred to as:

• A. Amplification
• B. Attenuation
• C. Filtration
• D. Rectification✓

Explanation: Rectification – Correct: Rectification is the process of converting AC to DC, typically using diodes.

Q75. Consider three-point charges A, B, and C as shown in the figure. If the resultant force on charge A due to charge B and charge C is 0.024 N, the direction of resultant force will be:

• A. Towards Charge A
• B. Towards Charge B
• C. Towards Charge C
• D. Vertical to the surface the charges are placed✓

Explanation: Vertical to the surface the charges are placed – Correct (likely): In many charge configurations, the resultant force has components in multiple directions, leading to a vertical resultant force. However, the exact answer depends on the charge arrangement in the missing figure.

Q76. The emf induced in a closed circuit is directly proportional to the rate of change of magnetic flux passing through the circuit" refers to:

• A. Lenz's law
• B. Faraday's law of electromagnetic induction✓
• C. Coulomb's law
• D. Ohm's law

Explanation: Faraday's law of electromagnetic induction – Correct: Faraday’s law states that the induced emf in a closed circuit is directly proportional to the rate of change of magnetic flux through the circuit.

Q77. A javelin is thrown by Arshad Nadeem at a projection angle of 45 degrees with an initial velocity of 30 m/s, the range of the javelin will be: (Consider g = 10 m/s²):

• A. 85m
• B. 90m✓
• C. 95m
• D. 100m

Explanation: Correct. Here's the calculation:Range formula for projectile motion:Range (R) = (v₀² * sin(2θ)) / gWhere:v₀ = initial velocity (30 m/s)θ = projection angle (45 degrees)g = acceleration due to gravity (10 m/s²)Calculate sin(2θ):sin(2 * 45°) = sin(90°) = 1Calculate the range:R = (30² * 1) / 10 = 900 / 10 = 90 m

Q78. If a pendulum completes one cycle in half a second, its frequency is

• A. 1 Hz
• B. 2 Hz✓
• C. 3 Hz
• D. 4 Hz

Explanation: Correct. Here's the calculation:Relationship between frequency and period:Frequency (f) = 1 / Period (T)Where:f = frequency (Hz)T = period (seconds)Given period:T = 0.5 secondsCalculate frequency:f = 1 / 0.5 = 2 Hz

Q79. The SI unit of electric charge is

• A. Ohm
• B. Farad
• C. Coulomb✓
• D. Ampere

Explanation: Coulomb – Correct: Coulomb (C) is the SI unit of electric charge, defined as the charge transported by a current of one ampere in one second.

Q80. At a stop light, a truck traveling at 15 m/s passes a car as it starts from rest. The truck travels at constant velocity, and the car accelerates at 3 m/s². How much time does the car take to catch up to the truck?

• A. 5 s
• B. 15 s
• C. 10 s✓
• D. 20 s

Explanation: Correct. Here's the calculation:Distance traveled by the truck:Distance_truck = velocity_truck * timeDistance_truck = 15t (where t is the time taken)Distance traveled by the car:Distance_car = initial_velocity_car * t + (1/2) * acceleration_car * t²Distance_car = 0 * t + (1/2) * 3 * t²Distance_car = 1.5t²When the car catches up, the distances are equal:Distance_truck = Distance_car15t = 1.5t²Solve for t:1.5t² - 15t = 01.5t(t - 10) = 0t = 0 (initial time) or t = 10 sTherefore the time taken is 10 seconds

Q81. A ball is in free fall. Its acceleration is:

• A. Downward during both ascent and descent✓
• B. Downward during ascent and upward during descent
• C. Upward during ascent and downward during descent
• D. Upward during both ascent and descent

Explanation: In free fall, the only force acting on the ball is gravity, which always points downward. Whether the ball is moving up or down, its acceleration due to gravity remains constant at 9.8 m/s² downward.

Q82. Which one of the following statements is correct for an object released from rest?

• A. The average velocity during the first second of time is 4.9 m/s✓
• B. During each second, the object falls 9.8 m
• C. The acceleration changes by 9.8 m/s² every second
• D. The object falls 9.8 m during the first second of time

Explanation: Since the object starts from rest and gains velocity due to gravity, its average velocity during the first second is 4.9 m/s.Given:The object is released from rest, so u=0 m/s Step 1: Motion under gravitySince the object is released from rest and falls freely, It is accelerating due to gravity, g=9.8 m/s^2 Step 2: Velocity after 1 secondUsing the equation of motion:v=u+(g)(t)v=0+9.8(1)=9.8 m/s The final velocity is 9.8 m/s downward.Step 3: Average velocityFor uniform acceleration, the average velocity is:v(avg)=(u+v)/2v(avg)=0+9.8/2 =4.9 m/s

Q83. Three persons X, Y, and Z wore pants of blue, khaki, and grey colors (not necessarily in this order) and shirts of white, blue, and pink colors (not necessarily in this order). No one wore pants and shirts of the same color.i. X did not wear a shirt of white color.ii. Y did not wear a shirt of blue color.iii. Z did not wear a shirt of pink color.iv. Y did not wear pants of blue color.v. Z wears pants of khaki color.What were the colors of pants and shirts (respectively) worn by X?

• A. Blue and pink✓
• B. Khaki and pink
• C. Green and blue
• D. Khaki and white

Explanation: A. Let's analyze the given conditions step by step:Given pants colors: Blue, Khaki, and Grey.Given shirt colors: White, Blue, and Pink.Z wears khaki pants.No one wore pants and shirts of the same color.Now, let's determine the shirt color for Z:Z did not wear a pink shirt (Condition iii).Since Z is already wearing khaki pants, he cannot wear a khaki shirt (not allowed).The remaining options for Z's shirt are white or blue.Now, let's determine Y’s pants color:Y did not wear blue pants (Condition iv).Since Z already took khaki pants, Y must have grey pants.Now, let’s determine Y’s shirt:Y did not wear a blue shirt (Condition ii).Y’s pants are grey, so he cannot wear a grey shirt.The remaining options for Y’s shirt are white or pink.Now, let's determine X’s clothing:X did not wear a white shirt (Condition i).The only remaining pants color for X is blue (since Z has khaki and Y has grey).X cannot wear a blue shirt (since no one can wear the same color pants and shirt).The only remaining shirt color for X is pink.Thus, X wore blue pants and a pink shirt.

Q84. Look carefully at the sequence of symbols to find the pattern. Select the correct pattern:

• A. Option A
• B. Option B✓
• C. Option C
• D. Option D

Explanation: This is the correct sequence because the diagrams in the image are moving backwards.

Q85. Statements:All men are hardworking.Some men are kings.Conclusions: I. All men are kings. II. All kings are hardworking.Based on the above statements, which conclusion(s) is drawn correctly?

• A. Only I
• B. Only II
• C. I and II
• D. Neither I nor II✓

Explanation: Neither I nor II – Correct. Since neither conclusion logically follows from the given statements, this is the correct answer.

Q86. Three students, X, Y, and Z and Y, and Z run faster than X, then who will win?

• A. X wins
• B. Y wins
• C. Z wins
• D. X wins and Y has a tie
• E. Data Insufficient✓

Explanation: Since there is not enough information to determine the winner between Y and Z, the question lacks a definitive answer.

Q87. Statements: A large number of people die every year drinking polluted water.Course of Actions: i. The government should make adequate arrangements in providing safe drinking water. ii. The people should be educated about the dangers of drinking polluted water.Which of the given suggested courses of action is/are logically worth to follow?

• A. If only course of action I follows
• B. If only course of action II follows
• C. If either course of action I or II follows
• D. If both courses of action I and II follow✓

Explanation: If both courses of action I and II follow – Correct. The problem can be effectively tackled if both actions are taken together.

Q88. Statements: i. The majority of the people in the locality belong to the low-income group. ii. The quality of the products in the local supermarket is considerably lower than those in the other localities.Which of the following answer choices correctly depicts the cause & effect relationship between these two statements?

• A. Statement I is the cause, and statement II is its effect✓
• B. Statement II is the cause, and statement I is its effect
• C. Both statements I and II are independent causes
• D. Both statements I and II are effects of a common cause

Explanation: Statement I is the cause, and statement II is its effect – Correct. Since the people in the locality have a low income, businesses may offer lower-quality products that are more affordable, making Statement I the cause and Statement II its effect.

Q89. The total number of moles present in 2.8 g of an ethylene molecule are:

• A. 0.1 g✓
• B. 0.2 g
• C. 1 g
• D. 2 g

Explanation: 0.1 g – Correct. The molar mass of ethylene (C₂H₄) is 28 g/mol. Moles = Mass / Molar Mass = 2.8 g / 28 g/mol = 0.1 moles.

Q90. Find the change in internal energy of the system when a system absorbs 2 kilocalorie of heat and at the same time does 500 joule of work

• A. 7900 J✓
• B. 8200 J
• C. 5600 J
• D. 6400 J

Explanation: Correct. Applying the first law of thermodynamics: ΔU = Q - W Q = 2 kcal = 2000 cal = 2000 × 4.186 J = 8372 J W = 500 J ΔU = 8372 J - 500 J = 7872 J ≈ 7900 J

Q91. The magnetic quantum number of the 4f orbital would be:

• A. -2, -3, -1, 0, +2, +3, +1, +4
• B. -2, -3, -1, 0, +2, +3, +1
• C. -3, -4, -2, -1, 0, +4, +3, +2, +1
• D. -3, -2, -1, 0, +1, +2, +3✓

Explanation: -3, -2, -1, 0, +1, +2, +3 – Correct. This includes all valid values for mₗ (-3 to +3) for an f-orbital. The magnetic quantum number (mₗ) ranges from -ℓ to +ℓ, where ℓ is the azimuthal quantum number for the given orbital. For an f-orbital, ℓ = 3, so mₗ can take values from -3 to +3.

Q92. Which of the following ions is readily hydrated?

• A. Mg2+✓
• B. Ba2+
• C. Na+
• D. Cs+

Explanation: The correct answer is Mg2+ because magnesium ions have a high charge (+2) and a small ionic radius, which allows them to effectively attract and hold onto water molecules, resulting in strong hydration. In contrast, Ba2+ ions, although also +2 charged, are larger and therefore less effective at hydration due to lower charge density. Na+ and Cs+ ions have a +1 charge, leading to weaker hydration capabilities; with cesium being the largest ion, it is the least hydrated of the options.

Q93. What is the IUPAC name of the compound CH3-CH2(CH3)-CH2-CH2(CH3)-CH3?

• A. 1,2-Dimethylpentane
• B. 2,4-Dimethylpentane✓
• C. n-Heptane
• D. Di-isoheptane

Explanation: The correct IUPAC name for the compound CH3-CH2(CH3)-CH2-CH2(CH3)-CH3 is 2,4-dimethylpentane. To arrive at this name, you first identify the longest continuous carbon chain, which contains five carbon atoms (pentane). Next, you identify the positions of the two methyl branches, which are located on the second and fourth carbons of the main chain.Option A, 1,2-dimethylpentane, incorrectly places the methyl groups on the first and second carbons, which does not reflect the correct branching of the compound. Option C, n-heptane, incorrectly identifies the compound as a straight chain of seven carbons, while it actually has branching. Option D, di-isoheptane, is not a valid IUPAC name for this structure, as it does not follow the systematic naming conventions.

Q94. What is the IUPAC name of the compound CH2= CH-CH=CH3-CH=CH-CH3?

• A. 1,3,5-Heptatriene✓
• B. 2,4,6-Heptatriene
• C. Hepta-1,3,5-triene
• D. Hepta-2,4,6-triene

Explanation: The correct answer is 1,3,5-Heptatriene because it accurately describes the structure of the compound CH2=CH-CH=CH3-CH=CH-CH3 with double bonds at the 1st, 3rd, and 5th carbon atoms. The longest continuous carbon chain comprises seven carbon atoms, which is indicated by the prefix 'hept-'. The suffix 'triene' signifies the presence of three double bonds.Option B, 2,4,6-Heptatriene, is incorrect because it misplaces the double bonds in the structure. Options C and D, while identifying the same structure, do not follow the conventional IUPAC naming format and are less preferred. Therefore, while C is technically correct, the standardized IUPAC name is preferred for clarity and consistency.

Q95. How many active sets of electrons are in water (H2O)?

• A. 2
• B. 3
• C. 4✓
• D. 8

Explanation: Water (H2O) is comprised of two hydrogen atoms and one oxygen atom. Each hydrogen atom contributes one valence electron, while the oxygen atom contributes six valence electrons, making a total of eight electrons. However, in terms of active sets, we consider the bonding pairs and lone pairs. The oxygen atom forms two single covalent bonds with the hydrogen atoms, resulting in two active sets of bonding electrons. Additionally, oxygen has two lone pairs of electrons, which adds two more active sets, leading to a total of four active sets of electrons in the molecule. Thus, the correct answer is four. Options A (2) and B (3) do not reflect the complete bonding structure, while option D (8) incorrectly suggests an excess of active sets.

Q96. When alkaline earth metals react with nitrogen, the compound formed is:

• A. M3N2✓
• B. M2N2
• C. M2N3
• D. M3N3

Explanation: When alkaline earth metals (group 2 elements) react with nitrogen, they typically form compounds with the formula M3N2, where M represents the alkaline earth metal. This occurs because each alkaline earth metal generally has a +2 oxidation state, allowing it to bond with nitrogen (which typically has a -3 oxidation state). Thus, in a balanced reaction, three metals will combine with two nitrogen atoms to form the compound M3N2. The other options do not reflect the correct stoichiometry based on the oxidation states of the elements involved.

Q97. The solubility of AgCl decreases by adding:

• A. H2SO4
• B. HF
• C. NaCl✓
• D. H2O

Explanation: The correct answer is NaCl because it provides Cl- ions, which are a common ion with AgCl (AgCl is composed of Ag+ and Cl- ions). The presence of the common ion (Cl-) shifts the equilibrium of the dissolution reaction of AgCl to the left, thereby decreasing its solubility according to Le Chatelier's principle.In contrast, H2SO4 and HF do not provide a common ion that interacts with AgCl, so they do not significantly influence its solubility. H2O merely dilutes the solution without affecting the ion concentration needed to alter AgCl solubility.

Q98. Repulsion between lone pairs of electrons is:

• A. Low
• B. No repulsion
• C. High✓
• D. Moderate

Explanation: The correct answer is High because lone pairs of electrons are located closer to the nucleus of an atom and occupy more space than bonding pairs, resulting in greater repulsion. This phenomenon can alter molecular geometry and is a key consideration in theories such as VSEPR (Valence Shell Electron Pair Repulsion).Options such as Low and No repulsion are incorrect because they underestimate the effects of lone pairs. The option Moderate is also incorrect as it misrepresents the strength of lone pair repulsion, which is distinctly categorized as high compared to bonding pairs.

Q99. Which is the correct sequence of electron filling in subshells?

• A. 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s✓
• B. 1s, 2s, 3s, 3p, 3d, 4p, 4s, 5s
• C. 1s, 2p, 3s, 3d, 4s, 4p, 5s
• D. 1s, 2s, 2p, 3s, 4s, 4p, 3d

Explanation: The correct answer is Option A: 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s. This sequence follows the Aufbau principle, where electrons fill subshells in order of increasing energy. The order of filling is determined by the relative energy levels of the subshells, with 4s being filled before 3d despite its higher principal quantum number.Option B is incorrect because it fills 4s after 3p and 3d, which does not reflect the correct energy order. Option C is incorrect as it skips the filling of the 2s subshell and improperly orders the 3d subshell. Option D fills 4s before 3d, which is also incorrect. Understanding the energy levels of subshells is essential to correctly answering this question.

Q100. Which of the following is not a redox reaction?

• A. CaCO3 ------ Ca + CO3✓
• B. Fe2+ ---- Fe3+
• C. 2H2 + O2 ------ 2H2O
• D. Cu2+ + 2e- ----- Cu

Explanation: The correct answer is Option A:CaCO3 ------ Ca + CO3because this reaction does not involve any transfer of electrons or changes in oxidation states, which are the hallmarks of redox reactions. In contrast, Options B, C, and D all involve either oxidation or reduction processes: Option B involves the oxidation of Fe2+ to Fe3+, Option C involves the reduction of O2 and oxidation of H2, and Option D shows the reduction of Cu2+ to Cu. Thus, they are all classified as redox reactions.

Q101. In Cannizzaro's reaction, formaldehyde reacts with:

• A. Chloroform
• B. NaOH✓
• C. Water
• D. HCL

Explanation: Cannizzaro's reaction is a unique organic reaction in which aldehydes that lack alpha-hydrogens undergo disproportionation in the presence of a strong base, such as sodium hydroxide (NaOH). In this process, formaldehyde is converted into methanol and sodium formate. Thus, NaOH is essential for facilitating the reaction. The other options are incorrect because chloroform does not react with formaldehyde in this context, water is a product rather than a reactant, and HCl is an acid that does not provide the necessary conditions for Cannizzaro's reaction to occur.

Q102. Carboxylic acids react with which of the following to form acyl halides?

• A. SOCl2✓
• B. HCl
• C. NaCl
• D. None of these

Explanation: Carboxylic acids can react with thionyl chloride (SOCl2) to form acyl halides, specifically acyl chlorides. The reaction involves the replacement of the hydroxyl group (-OH) of the carboxylic acid with a chlorine atom, resulting in the formation of the corresponding acyl chloride. This reaction is favored because SOCl2 is a strong chlorinating agent and drives the reaction to completion.In contrast, HCl is not strong enough to facilitate this transformation effectively; it is more likely to remain as a byproduct without converting the functional group. Sodium chloride (NaCl) is simply a salt with no reactive properties to convert the carboxylic acid into an acyl halide, as it does not provide the necessary halogen substitution.

Q103. Which of the following is more acidic?

• A. HF
• B. HCl
• C. HBr
• D. HI✓

Explanation: HI is the most acidic among the options given because it completely dissociates in water, releasing protons effectively. The bond between H and I is weaker compared to those in HF, HCl, and HBr, facilitating this dissociation. In contrast, HF is a weak acid due to the strong H-F bond, which resists breaking. While HCl and HBr are strong acids, they don't surpass HI in terms of acidity as they are less effective in proton donation compared to HI.

Q104. What is the general formula of an alkene?

• A. CnH2n✓
• B. CnH2n+2
• C. CnH2n-2
• D. None of these

Explanation: The correct answer isCnH2nIt, which represents the general formula for alkenes. In this formula, 'n' denotes the number of carbon atoms, and '2n' indicates the number of hydrogen atoms, accounting for the double bond that distinguishes alkenes from other hydrocarbon types. The other options are incorrect:CnH2n+2describes alkanes, which are saturated hydrocarbons;CnH2n-2corresponds to alkynes, which contain triple bonds; andNone of theseis incorrect because option A is valid.

Q105. Grignard reagent reacts with CO2 to form:

• A. Ester
• B. Alkane
• C. Carboxylic acid✓
• D. Ketone

Explanation: Grignard reagents are organomagnesium compounds that act as strong nucleophiles. When they react with carbon dioxide (CO2), they add to the carbon atom of the CO2 molecule, leading to the formation of a magnesium salt of a carboxylic acid. Upon hydrolysis, this salt is converted to a carboxylic acid. Hence, the correct answer is Carboxylic acid.Other options are incorrect because an ester is not formed directly from this reaction, nor are alkanes or ketones produced in this specific process. Alkanes are saturated hydrocarbons, while ketones are typically produced from different organic reactions.

Q106. Grignard reagent reacts with ------ to form carboxylic acid:

• A. CO2✓
• B. H2O
• C. Alcohol
• D. Ester

Explanation: The correct answer is CO2 because Grignard reagents react with carbon dioxide to form carboxylic acids. In this reaction, the Grignard reagent acts as a nucleophile, attacking the electrophilic carbon in CO2. This leads to the formation of a carboxylate ion, which upon acidification gives the corresponding carboxylic acid.The other options are incorrect as follows: H2O reacts with Grignard reagents but destroys them forming hydrocarbons; Alcohol leads to the formation of alkoxides, not carboxylic acids; and Ester reactions lead to tertiary alcohols instead of carboxylic acids.

Q107. In ethene, how many unhybridized p orbitals overlap to form π bonds?

• A. 1
• B. 2✓
• C. 4
• D. 8

Explanation: In ethene (C2H4), each carbon atom undergoes sp2 hybridization, resulting in three sp2 hybrid orbitals and one unhybridized p orbital per carbon. The two unhybridized p orbitals (one from each carbon) overlap side-by-side to form a π bond. Therefore, the correct answer is 2 unhybridized p orbitals. The other options are incorrect as they either miscount the number of orbitals or do not reflect the bonding mechanism in ethene.

Q108. Which of the following does not belong to the s-block?

• A. Li
• B. Cs
• C. Fe✓
• D. He

Explanation: The correct answer is Fe because iron is located in the d-block of the periodic table, which includes transition metals and does not belong to the s-block. The s-block elements are primarily found in groups 1 and 2, which include metals like lithium (Li) and cesium (Cs), both of which are alkali metals. Helium (He), while located in group 18, is still classified as part of the s-block due to its electron configuration. Thus, Fe is the only option that does not belong to the s-block.

Q109. The number of electrons in a shell is is:

• A. n2
• B. 2n2✓
• C. 2 l + 2
• D. 2 (l + 2)

Explanation: The formula for calculating the maximum number of electrons in a shell is given by 2n2, where 'n' is the principal quantum number associated with the shell. This means that for each shell, the number of electrons it can hold increases with the square of the principal quantum number, multiplied by 2. For example, the first shell (n=1) can hold 2 electrons, the second shell (n=2) can hold 8 electrons, and so forth.Option A (n2) is incorrect because it does not include the factor of 2. Options C (2 l + 2) and D (2 (l + 2)) are both incorrect as they relate to the angular momentum quantum number 'l' and do not apply to the total number of electrons in a shell.

Q110. The number of electrons in the M shell is:

• A. 2
• B. 10
• C. 18✓
• D. 6

Explanation: The M shell is the third shell in the electron configuration of an atom, corresponding to n=3. The formula to determine the maximum number of electrons in any shell is 2n². For the M shell, substituting n with 3 gives us 2(3)² = 2 x 9 = 18 electrons. Therefore, the correct answer is 18. The other options are incorrect because they do not reflect the maximum capacity of the M shell.

Q111. Which of the following showvs maximum ideal behavior?

• A. He✓
• B. H2
• C. CO2
• D. SO2

Explanation: The correct answer is He because helium is a noble gas that is monatomic and has minimal intermolecular forces, making it behave very closely to an ideal gas. In contrast, H2 while relatively ideal, still has some intermolecular attractions due to its diatomic nature. CO2 and SO2 have stronger intermolecular forces due to their molecular structure and polarity, which leads to greater deviations from ideal gas behavior.

Q112. Which law defines that if a chemical reaction can occur through multiple pathways, the net enthalpy change remains the same provided the initial and final states are the same?

• A. Hooke's Law
• B. Hess's Law✓
• C. First Law of Thermodynamics
• D. Henry's Law

Explanation: Hess's Law is the correct answer because it specifically addresses how the total enthalpy change in a chemical reaction is independent of the pathway taken, as long as the initial and final states remain unchanged. This is a fundamental principle in thermodynamics that allows chemists to calculate the enthalpy changes for reactions that are difficult to measure directly by using other, simpler reactions.In contrast, Hooke's Law deals with mechanical properties of materials (specifically springs), the First Law of Thermodynamics focuses on energy conservation without specifying enthalpy changes between states, and Henry's Law is concerned with the behavior of gases in liquids. Therefore, these options do not apply to the question about enthalpy and chemical pathways.

Q113. Which element is reduced in the equation Cl2+H2S →HCI+S?

• A. Cl2✓
• B. S
• C. H2
• D. H2S

Explanation: In the given reaction, Cl2 is the element that is reduced. Reduction involves gaining electrons, and in this case, chlorine gains electrons to form HCl. The oxidation state of chlorine decreases as it is converted from Cl2 to HCl, indicating it has been reduced. On the other hand, sulfur (S) is produced from H2S, which is oxidized during the reaction, making it incorrect to identify it as reduced. Hydrogen gas (H2) and hydrogen sulfide (H2S) do not gain electrons, thus they are not reduced either.

Q114. Sigma bonds are formed by:

• A. Linear overlapping✓
• B. Sidewise overlapping
• C. Lateral overlapping
• D. Parallel overlapping

Explanation: The correct answer is Option A: Linear overlapping. Sigma bonds are formed when two atomic orbitals overlap linearly, which allows for a strong and stable bond. This type of overlap occurs when atomic orbitals, usually s or p orbitals, align end to end. In contrast, the other options describe types of overlap that do not lead to sigma bond formation. Option B: Sidewise overlapping describes how pi bonds are formed, which is through the side-to-side overlap of p orbitals. Option C: Lateral overlapping is also associated with pi bonds and does not create sigma bonds. Finally, Option D: Parallel overlapping is characteristic of pi bonding as well, as it involves orbitals that overlap parallel to each other rather than in a head-on manner. Therefore, the only correct choice that describes sigma bond formation is linear overlapping.

Q115. Unequal distribution of alkyl groups on both sides of a carbon atom is known as:

• A. Tautomerism
• B. Metamerism✓
• C. Functional isomerism
• D. Structural isomerism

Explanation: The correct answer is Metamerism, which specifically addresses the situation where alkyl groups are unequally distributed around a carbon atom, leading to different structural isomers. In metamerism, the structural differences arise from varying arrangements of the alkyl groups on either side of a functional group, particularly in compounds like ethers or amines.On the other hand, Tautomerism involves isomers that readily interconvert, usually differing in the positioning of a proton and a double bond. Functional isomerism refers to isomers that have the same molecular formula but different functional groups, which does not apply here. Lastly, while Structural isomerism is a broader term that includes types like metamerism, it does not capture the specific aspect of unequal alkyl distribution.

Q116. Dehydration of alcohol gives:

• A. Alkane
• B. Alkene✓
• C. Alkyne
• D. Ester

Explanation: Dehydration of alcohol involves the elimination of a water molecule from the alcohol, which typically results in the formation of an alkene, as it creates a carbon-carbon double bond. This is a common reaction in organic chemistry where alcohols lose water to form alkenes. The other options are incorrect because:Alkane: This would require the addition of hydrogen rather than the removal of water, as alkanes are saturated.Alkyne: The formation of alkynes involves the creation of triple bonds, which does not occur during alcohol dehydration.Ester: While esters are formed from alcohols, they typically result from a reaction with carboxylic acids, not from dehydration of alcohol alone.

Q117. The bond angle between C-C in dịamond is:

• A. 104.5°
• B. 109°✓
• C. 180°
• D. 90°

Explanation: The correct bond angle between C-C in diamond is 109°, which arises from its tetrahedral arrangement of carbon atoms. In diamond, each carbon atom is bonded to four other carbon atoms at equal angles, leading to this specific bond angle due to sp3 hybridization. The other options are incorrect: 104.5° is associated with water's bent structure, 180° corresponds to linear molecules, and 90° relates to octahedral geometries, none of which apply to diamond's tetrahedral structure.

Q118. In methanol, the hybridization of carbon is:

• A. sp3✓
• B. sp2
• C. sp
• D. sp2d

Explanation: In methanol (CH3OH), the carbon atom is bonded to three hydrogen atoms and one hydroxyl group (–OH). This configuration requires four sigma bonds, which corresponds to sp3 hybridization. The carbon atom's four valence electrons hybridize to form four equivalent sp3 hybrid orbitals, which then form sigma bonds with the surrounding atoms.The other options are incorrect because:sp2: This would imply the presence of a double bond or a pi bond, which does not occur in methanol.sp: This indicates two sigma bonds and two pi bonds, which does not match the bonding in methanol.sp2d: This hybridization involves d orbitals, which are not utilized by carbon in methanol.

Q119. Which reaction occurs at the cathode?

• A. Oxidation
• B. Reduction✓
• C. Redox
• D. None

Explanation: At the cathode, reduction occurs, meaning that the species present gains electrons. This is in direct contrast to the anode, where oxidation (loss of electrons) occurs. Therefore, the correct answer is Reduction. The other options are incorrect as follows: Oxidation takes place at the anode, not the cathode; Redox describes the overall process but does not specify the cathode reaction; and None is incorrect because a reaction does occur at the cathode.

Q120. Which catalyst is used in the halogenation of benzene?

• A. Ni
• B. Fe
• C. FeCl3✓
• D. N2O5

Explanation: The correct answer is FeCl3, which is commonly used as a catalyst in the halogenation of benzene. This catalyst facilitates the generation of a halogen cation (electrophile) that can attack the aromatic ring in a substitution reaction. The other options are incorrect because:Ni: Nickel is typically used in hydrogenation reactions, not halogenation.Fe: While iron can be a catalyst in some reactions, it is not effective for the halogenation of benzene.N2O5: This compound is not relevant to the halogenation process and is more associated with oxidation reactions.

Q121. The electrophile in the nitration of benzene is:

• A. NO+
• B. NO2+✓
• C. N2O5+
• D. NO3+

Explanation: The correct answer is NO2+, which is the nitronium ion. It is the primary electrophile in the nitration of benzene, facilitating the introduction of a nitro group onto the aromatic ring. The other options are incorrect because:NO+ is a nitrosyl ion and does not participate in the nitration of benzene.N2O5+ can theoretically generate nitronium ions but is not the direct electrophile in the reaction.NO3+ refers to a nitrate ion, which does not act as the electrophile in this specific nitration reaction.Thus, understanding the role of the nitronium ion is crucial for mastering electrophilic aromatic substitution reactions.

Q122. Another name of London dispersion forces (LDF) is:

• A. Instantaneous dipole-induced dipole force✓
• B. Dipole force
• C. Ion-dipole force
• D. Electrostatic force

Explanation: London dispersion forces (LDF) are also known as instantaneous dipole-induced dipole forces because they arise when the electron distribution in a molecule creates a temporary dipole, which can then induce a dipole in a neighboring molecule. This force is particularly significant in non-polar molecules. The other options do not accurately describe LDF. 'Dipole force' refers to forces between permanent dipoles, 'ion-dipole force' involves interactions between ions and polar molecules, and 'electrostatic force' encompasses a broader range of forces between charged entities. Thus, the correct answer is option A.

Q123. The IUPAC name of picric acid is:

• A. 1,2,3-Trimethyl xylene
• B. 1,2,3-Trimethyl phenol
• C. 2,4,6-Trimethyl phenol
• D. None✓

Explanation: The correct IUPAC name for picric acid is 2,4,6-trinitrophenol, which indicates that it has three nitro (–NO2) groups attached to a phenolic structure at the 2, 4, and 6 positions. The other options incorrectly suggest the presence of methyl groups instead of nitro groups. Therefore, all other options are incorrect as they do not accurately reflect the structure of picric acid.

Q124. VWhich has the same unit as work?

• A. Heat✓
• B. Power
• C. Mole
• D. Mass

Explanation: The correct answer is Heat, as both work and heat are measured in joules (J), which is the standard unit of energy in the International System of Units (SI). In contrast, Power is expressed in watts (W), which is derived from joules per second; therefore, it does not share the same unit as work. Mole is a unit of measurement for the quantity of substance, and Mass is quantified in kilograms. Neither of these relates to work or energy transfer.

Q125. In what ratio are nitrogen and hydrogen present in the formation of ammonia?

• A. 1:2
• B. 1:3✓
• C. 5:2
• D. 1:4

Explanation: Ammonia (NH3) is formed when nitrogen (N2) reacts with hydrogen (H2) in a 1:3 ratio. This means that for every 1 molecule of nitrogen, 3 molecules of hydrogen are needed. Thus, the correct option is 1:3. Other options are incorrect as they do not follow the correct stoichiometric ratios for the formation of ammonia, which are derived from its chemical formula.

Q126. Reduction of benzene gives:

• A. Cyclohexane✓
• B. Phenol
• C. Anthracene
• D. Toluene

Explanation: The correct answer is Cyclohexane, which is formed when benzene undergoes a reduction reaction, typically through catalytic hydrogenation. This process leads to the saturation of the benzene ring, converting its double bonds into single bonds, resulting in cyclohexane.The other options are incorrect because:Phenol is produced by the hydroxylation of benzene, not through reduction.Anthracene is a larger polycyclic aromatic compound, not a product of benzene reduction.Toluene is created through the introduction of a methyl group to benzene, rather than being a product of its reduction.

Q127. Which is a trihydric alcohol?

• A. Xylene
• B. Hydroquinone
• C. Resorcinol
• D. Pyrogallol✓

Explanation: The correct answer is Pyrogallol because it contains three hydroxyl (-OH) groups in its structure, qualifying it as a trihydric alcohol. In contrast, Xylene is an aromatic hydrocarbon and has no hydroxyl groups, making it irrelevant to this question. Hydroquinone and Resorcinol both contain only two hydroxyl groups, classifying them as dihydric alcohols, thus they do not fit the criteria for trihydric alcohols.

Q128. Alcohol reacts with PCl5 to form:

• A. Aldehyde
• B. Ketone
• C. Alkyl halide✓
• D. Ester

Explanation: The correct answer is alkyl halide. When alcohol reacts with phosphorus pentachloride (PCl5), the hydroxyl group (-OH) of the alcohol is replaced by a chlorine atom, resulting in the formation of an alkyl halide. This reaction is a substitution reaction where the alcohol is converted into a more reactive alkyl halide.The other options are incorrect for the following reasons:Aldehyde: Aldehydes are formed through oxidation of primary alcohols, not through reaction with PCl5.Ketone: Ketones are typically produced from secondary alcohols through oxidation, not from direct reaction with PCl5.Ester: Esters are formed from the reaction of alcohols with carboxylic acids, not from PCl5.

Q129. Which test differentiates alcohol and phenol?

• A. Na metal test✓
• B. Ester test
• C. Tollen's reagent
• D. Benedict's test

Explanation: The correct answer is the Na metal test, which effectively distinguishes between alcohols and phenols based on their different reactivity with sodium metal. Alcohols react with sodium to generate hydrogen gas, while phenols show minimal reaction. The Ester test is unrelated since it focuses on identifying esters rather than differentiating between alcohols and phenols. Although Tollen's reagent can be used in organic chemistry for identifying aldehydes, it does not serve to differentiate between alcohols and phenols. Similarly, the Benedict's test is designed for detecting reducing sugars, making it irrelevant in the context of functional group differentiation.

Q130. Which is a meta-directing group?

• A. Cl
• B. NO2✓
• C. R --- OH
• D. R --- NH2

Explanation: The correct answer is NO2, which is classified as a meta-directing group due to its electron-withdrawing properties that destabilize the negative charge in the intermediate during electrophilic aromatic substitution. In contrast, Cl, R --- OH, and R --- NH2 are all considered ortho/para-directing groups. Chlorine (Cl) is a weak electron-withdrawing group but does not stabilize the negative charge effectively in the meta position. Both hydroxyl (R --- OH) and amino (R --- NH2) groups are strong electron-donating groups that direct electrophiles to the ortho and para positions, not to the meta position.

Q131. The shape of iodotrichloride (ICI3) is:

• A. Trigonal planar✓
• B. Pyramidal
• C. Bipyramidal
• D. Linear

Explanation: The correct shape of iodotrichloride (ICI3) is trigonal planar. This geometry arises because the iodine atom is surrounded by three chlorine atoms, forming three sigma bonds and having no lone pairs. The arrangement minimizes electron pair repulsion, leading to a flat, trigonal shape. On the other hand, the pyramidal option suggests the presence of a lone pair on the iodine, which is not the case here. The bipyramidal option is incorrect as it requires five bonding pairs, while the linear shape is only applicable to molecules with two bonding pairs. Thus, the trigonal planar arrangement is the only correct answer.This paper contains fewer questions than the original exam because the official paper was not released by the testing agency. However, these questions represent the maximum number we could find and should provide a fairly good idea of the actual paper’s content and pattern.