Punjab Chemistry 2017 Paper 1 — Solved MCQs

Question 1

Keeping in view the size of atoms,which order is correct one?

Accepted Answer

B. Ba>Mg — Since barium is placed lower than magnesium i.e., at the bottom in the second group of periodic table, therefore barium atom are larger in size than magnesium atom and hence barium atoms loses its valence electron more readily than magnesium atom and forms positive ions i.e., cation.

Question 2

Which ion will have maximum value of heat of hydration?

Accepted Answer

B. Cs” — Therefore, lithium ion ($L{{i}^{+}}$) has the highest polarizing power. This polarizing power of the lithium is explained by the size and charge of the ion, as we know that the size of the lithium in the alkali metal ions is the smallest, due to which the ratio of charge and size is very high.

Question 3

Which element among the following belongs to group IVA of periodic table?

Accepted Answer

C. Tin — Tin is a chemical element found in Group 14 (or IVa) of the periodic table (i.e., the carbon family). The tin element symbol is Sn, which is derived from the Latin name for the element - stannum. It is a silvery-white metal that is resistant to corrosion. The atomic number of tin is 50 and atomic mass is 118.71.

Question 4

The oxidation of NO in air produces:

Accepted Answer

D. N,O, — Eventually, NO2 is oxidised to nitric acid (HNO3, vapour) which is absorbed directly at the ground, is converted into nitrate-containing particles, or dissolves in cloud droplets.

Question 5

Which halogen will react spontaneously with Au(s) to produce Au’?

Accepted Answer

D. cl2 — Chlorine ( Cl2 ) is the halogen react spontaneously with gold to produce gold ions.

Question 6

Which of the following is a typical transition metal?

Accepted Answer

C. Co — Group IIB elements (Zn, Cd and Hg) do not have a partially filled d-subshell either as elements or in any of their ionic state. Neither do they show typical properties of transition elements to any appreciable extent (except complex formation). Similarly, IIIB (Sc, Y and La) is another group of elements which do not show many of the properties associated with typical transition elements.

Question 7

In t-butyl alcohol, the tertiary carbon atom is bonded to:

Accepted Answer

D. no hydrogen atom — tert-butyl alcohol is also called 2-methylpropan-2-ol in IUPAC system. Here the tertiary Carbon is bonded to three methyl groups and one OH group. And no hydrogen atom is bonded to the tertiary Carbon.

Question 8

The presence of double bond in a compound is sign of:

Accepted Answer

B. Unsaturation — Compounds containing double bonds are said to be unsaturated because they are capable of reacting with hydrogen in the presence of a catalyst. The resulting compounds, which contain no multiple bonds, are said to be saturated.

Question 9

Which of the following acid can be used as a catalyst in Friedal-craft reactions?

Accepted Answer

B. AICI, 3 — Aluminium trichloride (AlCl3) is often used as a catalyst in Friedel-Crafts reactions since it acts as a Lewis acid and coordinates with the halogens, generating an electrophile in the process.

Question 10

SN, reactions can be best carried out with:

Accepted Answer

A. Primary alkyl Halide ( — Primary alkyl halides undergo SN2 reaction in a faster rate than secondary and tertiary. Of the simple alkyl halides, methyl halides react most rapidly in SN2 reactions because there are only three small hydrogen atoms.

Question 11

Which compound shows maximum hydrogen bonding with water?

Accepted Answer

C. CH3-O-CH3 — Hydrogen bonding is defined as the formation of hydrogen bonds, which are a special type of attractive intermolecular forces that arise due to the dipole-dipole interaction between a hydrogen atom that is bonded to a highly electronegative atom and another highly electronegative atom that lies next to the hydrogen atom.In ethanol, Hydrogen is bound to more electronegative oxygen than triethylamine, where Hydrogen is bound to less electronegative nitrogen, which can be shown as;Hence, Hydrogen bonding is maximum in ethanol.

Question 12

Ketones are prepared by oxidation of:

Accepted Answer

B. secondary alcohol — The oxidation of alcohols is an important reaction in organic chemistry. Primary alcohols can be oxidized to form aldehydes and carboxylic acids; secondary alcohols can be oxidized to give ketones. Tertiary alcohols, in contrast, cannot be oxidized without breaking the molecule's C–C bonds.

Question 13

Which acid is used in manufacture of synthetic fiber?

Accepted Answer

C. acetic acid — Acetic acid is used in the synthesis of cellulose acetate, which is a synthetic fiber.

Question 14

Which of the following is not a fatty acid?

Accepted Answer

B. acetic acid — The term “acetic” comes from “acetum,” the Latin word for vinegar. Acetic acid is a short-chain fatty acid that dissolves into acetate and hydrogen in your body. About 5–6% of apple cider vinegar consists of acetic acid. It also contains water and trace amounts of other acids, such as malic acid

Question 15

A polymeric substance that is formed in the liquid state and then hardened to a rigid solid is called a:

Accepted Answer

D. polyamide resin — In materials science, a thermosetting polymer, often called a thermoset, is a polymer that is obtained by irreversibly hardening ("curing") a soft solid or viscous liquid prepolymer (resin).

Question 16

Phosphorous helps the growth of:

Accepted Answer

A. Root — Phosphorus promotes healthy root growth, promotes early shoot growth, speeds ground cover for erosion protection, enhances the quality of fruit, vegetable and grain crops, and is vital to seed formation.

Question 17

To avoid the formation of toxic compounds with chlorine which substance is used for disinfecting water:

Accepted Answer

B. chloramines — Most municipal drinking water treatment facilities now use chloramines instead of freely available chlorine to prevent the production of THMs. Ammonia is simply added to chlorine to create chloramines.

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