Question

The reaction a(g)+2b(g)→c(g)+d(g) is an elementary process. In an experiment, the initial pressure of a and b are Pa​ atm and Pb​ atm. When t, the rate of the reaction relative to the initial

Options:
a. Pa​​/2
b. Pa/Pb​​​
c. 2Pa/Pb​​​
d. Pb/Pa​​​

Answer 1

The rate law for the elementary reaction a(g) + 2b(g) → c(g) + d(g) is rate = k[Pa][Pb]^2, indicating first-order dependence on reactant A and second-order dependence on reactant B. The rate will vary directly with Pa and the square of Pb.

Step-by-step explanation:

The student's question revolves around the concept of reaction rates for elementary processes in chemistry. For the elementary reaction a(g) + 2b(g) → c(g) + d(g), the rate law can be directly deduced from the stoichiometry because the order of reaction is the same as the molecularity. Therefore, if the initial pressures are Pa atm for A and Pb atm for B, then the rate of reaction can be expressed by the rate law:

rate = k[Pa][Pb]^2

This implies that the rate of the reaction is directly proportional to the pressure of A and the square of the pressure of B. The equation also indicates the reaction is first-order with respect to A and second-order with respect to B. It's important to note that for elementary processes, the rate law reflects the stoichiometry of the reactants.