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 statements regarding hydrogen is wrong?

  1. Hydrogen has three isotopes.

  2. Hydrogen may be prepared by the action of hot 20% NaOH on silicon.

  3. Nascent hydrogen reduces ferric chloride to ferrous chloride.

  4. Hydrogen gas is corrosive in nature.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

 Hydrogen cannot be prepared by the action of hot 20% NaOH on silicon.

Multiple choice

For the process of electrolysis of water, which of the following statements is true?

  1. Oxygen bubbles will be formed on positive electrode and hydrogen bubbles will be formed on negative electrode.

  2. Oxygen bubbles will be formed on negative electrode and hydrogen bubbles will be formed on positive electrode.

  3. Oxygen and hydrogen bubbles will be formed on positive electrode only.

  4. Oxygen and hydrogen bubbles will be formed on negative electrode only.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Oxygen bubbles will be formed on positive electrode and hydrogen bubbles will be formed on negative electrode.

Multiple choice

Which of the following turns passive by adding HNO3?

  1. Al

  2. Be

  3. Both 1 and 2

  4. Cu
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Both Al and Be become passive in concentrated HNO3 because the acid forms a thin, protective oxide layer on their surface that prevents further reaction. This passivation is characteristic of metals that form amphoteric oxides and occurs only with concentrated nitric acid.

Multiple choice

Carbon dioxide can be prepared by

  1. the reaction of tin with sulphuric acid

  2. the reaction of carbon with hydrochloric acid

  3. the reaction of marble with sulphuric acid

  4. the reaction of zinc with hydrochloric add
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Carbon dioxide can be prepared by the reaction of marble with sulphuric acid.

Multiple choice

Haber process is an example of

  1. heterogeneous catalysis

  2. homogeneous catalysis

  3. electrocatalysis

  4. organocatalysis

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

Heterogeneous catalysts act in a different phase than the reactants. Most heterogeneous catalysts are solids that act on substrates in a liquid or gaseous reaction mixture. For example, in the Haber process, finely divided iron serves as a catalyst for the synthesis of ammonia from nitrogen and hydrogen.

Multiple choice

Nitric acid is formed by

  1. Haber process

  2. Ostwald process

  3. Contact process

  4. Lead chamber process
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The Ostwald process is the industrial method for producing nitric acid from ammonia. It involves three steps: oxidation of ammonia to NO, oxidation of NO to NO2, and absorption of NO2 in water. The Haber process produces ammonia, Contact process produces sulfuric acid, and Lead chamber process is an older method for sulfuric acid production.

Multiple choice

Which of the following is used to dissolve noble metals?

  1. Nitric acid

  2. Hydrochloric acid

  3. Sulphuric acid

  4. Aqua regia
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Aqua regia (Latin for 'royal water') is a mixture of nitric acid and hydrochloric acid in 1:3 ratio. It can dissolve gold and platinum, which are 'noble' metals that resist most other acids. The chloride ions form soluble complexes with noble metal ions.

Multiple choice

Which of the following statements is/are false?

a. Rain water dissolves carbon dioxide gas from air and forms carbonic acid. b. The aqueous solution of an acid conducts electricity due to the presence of charged particles in it. c. Acids show acidic behaviour in the absence of water.

  1. Only a

  2. Only a and b

  3. Only b

  4. Only b and c

  5. Only c
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

This is the correct option as this statement is false. Acids do not show acidic behaviour in the absence of water.