Practicing Success

Target Exam

CUET

Subject

Chemistry

Chapter

Physical: Chemical Kinetics

Question:

Case: Read the passage and answer the following questions

In the rate equation Rate = k [A]x[B]y

 x and y indicate how sensitive the rate is to the change in concentration of A and B. Sum of these exponents, i.e., x + y gives the overall order of a reaction whereas x and y represent the order with respect to the reactants A and B respectively. Hence, the sum of powers of the concentration of the reactants in the rate law expression is called the order of that chemical reaction. Order of a reaction can be 0, 1, 2, 3 and even a fraction.

Which of the following is true for the value of rate constant of a pseudo first order reaction?

Options:

It depends on the concentration of the reactants present in small amount.

It is independent on the concentration of reactants.

It depends only on temperature.

It depends on the concentration of the reactants present in excess amount.

Correct Answer:

It depends on the concentration of the reactants present in excess amount.

Explanation:

The value of the rate constant of pseudo-first-order reaction depends on the concentration of reactants present in excess amount. A pseudo-first-order reaction can be defined as a second-order or bimolecular reaction that is made to behave like a first-order reaction.