Punjab Chemistry 2022 Paper 2 — Solved MCQs

Question 1

Which catalyst is used in contact process?

Accepted Answer

C. V2O5 — The Contact Process involves the oxidation of sulfur dioxide (SO2) to sulfur trioxide (SO3), which is then used to produce sulfuric acid.SO2 obtained by burning sulphur or iron pyrites is oxidized to SO3 in the presence of V2O5 which acts as a catalyst.

Question 2

Chlorine heptaoxide Cl2O1 reacts with water to form:

Accepted Answer

B. Perchloric acid — Chlorine heptoxide reacts vigorously with water to form perchloric acid (HClO4) and hydrochloric acid (HCl).

Question 3

Group VI B of transition elements contains:

Accepted Answer

C. Cr, Mo, W — Chromium (Cr), molybdenum (Mo), and tungsten (W) belong to Group VI B of transition elements. These elements are known for their characteristic chemistry and properties, such as forming colored compounds and exhibiting multiple oxidation states.

Question 4

The chemist who synthesized urea from ammonium cyanate was:

Accepted Answer

B. Fredrick Wohler — In 1828, he synthesized urea from ammonium cyanate, thereby disproving the theory of vitalism, which held that organic compounds could only be synthesized by living organisms. This experiment laid the foundation for organic chemistry

Question 5

Vinyl acetylene combines with HCl to form:

Accepted Answer

C. Chloroprene — When acetylene is passed through an acidic solution of cuprous chloride and ammonium chloride and then allowed to stand for several hours at room temperature, vinyl acetylene and divinyl acetylene are obtained. If HCl is added to vinyl acetylene, chloroprene is obtained which readily polymerize to neoprene, used as synthetic rubber.

Question 6

Aromatic compounds burn with sooty flame because:

Accepted Answer

C. They have high percentage of carbon — The aromatic compound displays aromaticity. They burn with a strong sooty yellow flame. A "sooty flame" indicates that incomplete combustion is occurring and the reason for this flame is the high percentage of carbon content. The carbon-hydrogen ratio is high in aromatic compounds.

Question 7

Elimination bimolecular reactions involve:

Accepted Answer

B. Second order kinetics — :Kinetic studies of the reactions involving E2 mechanism have shownthat the rates of such reactions depend upon the concentrations of alkylhalide as well as the attacking nucleophile. Mathematically, the ratecan be expressed as:Rate = k [Alkyl halide][Nucleophile]In E2 MECHANISM there is only one step so it is bimolecular

Question 8

Which compound will have the maximum repulsion with H2O?

Accepted Answer

A. C6H6 — Benzene (C6H6) will have the maximum repulsion with H2O because benzene is nonpolar and does not readily interact with polar molecules like water. The benzene ring has a symmetrical, planar structure with delocalized pi-electrons, making it non-reactive and unable to form strong hydrogen bonds with water molecules.

Question 9

Which of the following reagents will react with both aldehydes and ketones?

Accepted Answer

A. Grignard reagent — Grignard reagent (RMgX, where R is an alkyl or aryl group and X is a halogen) can react with both aldehydes and ketones to form alcohols. This reaction is known as a Grignard reaction and involves the nucleophilic addition of the Grignard reagent to the carbonyl group of the aldehyde or ketone, followed by protonation to give the alcohol.

Question 10

The solution of which acid is used for seasoning of food?

Accepted Answer

B. Acetic acid — Acetic acid is correct because it is commonly used for seasoning food. Acetic acid, also known as vinegar when diluted, is a weak acid that adds a sour flavor to foods and is widely used in cooking and food preparation.

Question 11

The fibre which is made from acrylonitrile as monomer?

Accepted Answer

C. Acrylic fibre — These are closely related to the vinyl resins. The most important monomers of acrylic resins are methylmethacrylate, acrylic acid and butyl acrylate. The acrylic fibres are based largely on acrylonitrile. Acrylic resins are used in the manufacture of plastics, paints for car industry and water based weather resistant paints.

Question 12

Which is not a calcarious material?

Accepted Answer

B. Clay — The important raw materials used for the manufacture of cement are:1. Calcarious material (limestone, marble, chalks, marine shell) as source of CaO.2. Argillaceous material (clay, shale, slate, blast furnace slag) They provide acidic components such as aluminates and silicates,3. Other raw material being used is gypsum.

Question 13

Newspaper can be recycled again and again by how many times?

Accepted Answer

D. 5 — 5 is correct because newspaper can typically be recycled about 5 to 7 times before the fibers become too short and weak to be used again in high-quality paper products. After multiple recycling cycles, the fibers become too degraded to be effectively reprocessed into new paper, so they are often used for lower-grade paper products or other materials.

Question 14

The normal amount of overhead ozone is about:

Accepted Answer

D. 350 DU — The amount of ozone in the atmosphere is expressed in Dobson units (DU). The normal amount of overhead ozone is about 350 DU.

Question 15

Mark the correct statement:

Accepted Answer

A. Na+is smaller than Na — When a neutral atom loses one or more electrons, it becomes a positive ion. The size of the atom is decreased in this process because of two reasons. First, the removal of one or more electrons from a neutral atom usually results in the loss of the outermost shell. Second, the removal of electrons causes an imbalance in the proton-electron ratio. Due to the greater attraction of the nuclear charge, the remaining electrons of the ion are drawn closer to the nucleus. Thus, a positive ion is always smaller than the neutral atom from which it is derived. The radius of Na is 157 pm, and the radius of Na+ is 95 pm

Question 16

Chile saltpetre has the chemical formula:

Accepted Answer

A. NaNO3 — NaNO3 is correct because Chile saltpetre, also known as sodium nitrate, has the chemical formula NaNO3. It is a naturally occurring mineral that is used in fertilizers, explosives, and food preservation.

Question 17

Which of the following elements is not present abundantly in earth's crust?

Accepted Answer

C. Sodium — Sodium is correct because it is not present abundantly in Earth's crust compared to silicon, aluminium, and oxygen. Sodium is a relatively reactive alkali metal and is not a major component of the Earth's crust.

Punjab Chemistry 2022 Paper 2 — Solved Past Paper with Answers

More Punjab / UHS Solved Papers