Question

Which of the following statements are correct about solid catalyst?

(i) Same reactants may give different product by using different catalysts.

(ii) Catalyst does not change ∆H of reaction.

(iii) Catalyst is required in large quantities to catalyse reactions.

(iv) Catalytic activity of a solid catalyst does not depend upon the strength of chemisorption.

Answer 1

(i) Same reactants may give different product by using different catalysts.

(ii) Catalyst does not change ∆H of reaction.

Explanation:

(i) Same reactants may give different products by using different catalysts as different catalysis have different specific functions to mould the reaction towards specific product, e.g., starting with H2 and CO, and using different catalysts, we get different products.

(i) \[\ce{CO (g) + 3H2 ->[Ni] CH4 (g) + H2O (g)}\]

(ii) \[\ce{Co (g) + 2H2 (g) ->[Cu/Zno] CH3OH (g)}\]

(iii) \[\ce{CO (g) + H2 (g) ->[Cu] HCHO (g)}\]

(ii) Catalyst does not change ∆H of reaction as ∆H of reaction is difference between enthalpy of reactants and products. So, it does not change during catalysed reaction.