Chemistry

Chemical Reactions and Processes

626 Questions

Chemical reactions and processes questions cover the transformation of substances through electrolysis, thermal decomposition, and catalysis. Key areas include identifying gas evolution, balancing chemical equations, and understanding industrial chemical applications. This general chemistry topic is a staple in the science sections of multiple competitive examinations.

Thermal decompositionElectrolysis processGas evolution reactionsHeterogeneous catalystsFuel cell components

Chemical Reactions and Processes Questions

Multiple choice

Which of the following are methods of preparation of nitric acid?

  1. Birkeland–Eyde process
  2. Deacon’s process
  3. Haber process
  4. Lead chamber process
  5. Ostwald process

Select the correct answer using codes given below:

  1. 1 and 3

  2. 1 and 5

  3. 2 and 4

  4. 2 and 5

  5. 3 and 4
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The Birkeland–Eyde process was used to fix atmospheric nitrogen (N2) into nitric acid (HNO3). The Ostwald process is a chemical process for making nitric acid.

Multiple choice

Why is fire extinguished by soda bicarbonate?

  1. Soda bicarbonate decompose on heating to produce carbon dioxide-gas which extinguishes fire.

  2. Soda bicarbonate serves as a blanket for fire.

  3. Soda bicarbonate releases water extinguishing the fire.

  4. None of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Sodium bicarbonate (baking soda) decomposes when heated to release carbon dioxide gas. Since carbon dioxide is denser than air and does not support combustion, it smothers the fire.

Multiple choice

Ammonification means

  1. conversion of complex nitrogenous compound into ammonia

  2. conversion of ammonia into nitrates

  3. conversion of nitrates into free nitrogen

  4. manufacturing ammonia in laboratory

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Ammonification is the process by which decomposers (bacteria and fungi) break down organic nitrogenous compounds (like proteins and amino acids) from dead organisms into ammonia.

Multiple choice

Assertion (A): Anhydrous MgCl2 cannot be prepared by direct heating of hydrated MgCl2. Reason (R): During the heating hydrolysis of MgCl2 takes place that produce MgO. Select the correct opinion.

  1. A is true, but R is false.

  2. A is false, but R is true.

  3. Both A and R are true.

  4. Both A and R are false.

  5. None of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Anhydrous magnesium chloride is regenerated from magnesium hydroxide or magnesium carbonate using hydrochloric acid. In order to obtain anhydrous magnesium chloride from hydrated form by heating, hydrolysis of MgCl2 takes place that produce MgO. Thus anhydrous MgCl2 cannot be prepared by direct heating of hydrated MgCl2. Hence, both A and R are true.

Multiple choice

Name the catalyst used in vegetable oils to make margarine.

  1. V2O5

  2. Ni

  3. Pt

  4. Al2O3

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

One important industrial use is in the hydrogenation of vegetable oils to make margarine, which also involves reacting a carbon-carbon double bond in the vegetable oil with hydrogen in the presence of a nickel catalyst. Ethene molecules are adsorbed on the surface of the nickel. The double bond between the carbon atoms breaks and the electrons are used to bond it to the nickel surface.

Multiple choice

Electrolysis of water results in the formation of

  1. hydrogen and nitrogen

  2. hydrogen and oxygen

  3. helium and argon

  4. carbon monoxide and oxygen
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Electrolysis of water involves passing an electric current through it, which decomposes the water molecules into their constituent elements, hydrogen gas and oxygen gas.

Multiple choice

Reaction of water with metal gives

  1. acid

  2. base

  3. amphoteric substance

  4. no product
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Active metals react with water to form metal hydroxides (which are basic) and hydrogen gas.

Multiple choice

By which of the following reactions can gold sol be prepared?

  1. Hydrolysis of gold(III) chloride

  2. Oxidation of gold by aqua regia

  3. By peptization

  4. Reduction of gold (III) chloride formalin solution

  5. None of these
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

This option is correct because gold chloride reacts with formaldehyde and water to give gold sol and formic acid.