Question

Assertion :A catalyst always lowers the energy of activation. Reason: Catalyst interact with reactant molecules to form adsorbed activated complex with evolution of energy.

• A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
• B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
• C. Assertion is correct but Reason is incorrect
• D. Assertion and Reason both are incorrect

Answer 1

The correct option is A Both Assertion and Reason are correct and Reason is the correct explanation for Assertion

A Catalyst is a substance which accelerates the rate of a chemical reaction without undergoing any change in its chemical composition or mass during the reaction. A catalyst accelerates the rate of a reaction by lowering the activation energy.

A catalyst works by providing a different route with lower activation energy,for the reaction. In any given time interval, the presence of a catalyst allows a greater proportion of the reactant species to acquire sufficient energy to pass through the transition state and become products.

$Catalyst+Reactant\stackrel{Adsorption}{\to }$ $Adsorbedactivatedcomplex$ ; $\Delta H=-ve$

Thus, intermediate possess lower energy level.