Q$3.$ a$)$ Write different steps associated with a gas phase solid catalytic reaction to form product.

The reaction is: $AB.$

b$)$ What do you mean by active sites in a solid catalyst? How do you express its concentration?

$1+1=2$

c$)$ From the following rate equation, state the reaction, adsorption mechanism and reaction kinetics with logic.

$1+2+2=5$

$-r_N^{\text{'}}=\frac{k{P}_N}{(1+K_1{P}_N+K_2{P}_C{)}^2}$

d$)$ Derive this rate law, considering a suitable rate limiting step consistent with the given rate expression as in the question c$).$ Keep all notations same and name the notations.