Question

(i) Catalyst are substances which.........chemical composition.
(a) do not change their
(b) partially change their
chemical composition.
(c) completely change their
(d) initially change and then restore​

Answer 1

(a) do not change their

Explanation:

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Answer 2

Answer:

The correct option is (d) Initially change and then restore their chemical composition.

Explanation:

• A catalyst can be defined as a substance which increases the rate of a reaction.
• It is required in a small quantity in order to accelerate a reaction.
• It may react with the reactants and later regenerate itself. It will not be present in the final products.
• The presence of a catalyst lowers the activation energy. This results in lesser energy requirement for reactants to react.

Conclusion:

The chemical composition of a catalyst initially changes and later restored.