Question

In a second-order reaction, the rate of the reaction is proportional to:

• A. The square of the concentration of the reactant
• B. The concentration of the reactant
• C. The concentration of the reactant raised to the third power
• D. The inverse of the concentration of the reactant

Hint:

In second-order reactions, always look for the squared term in the rate law—this helps distinguish it from first- or zero-order reactions.

Answer 1

The Correct Option is A

In chemical kinetics, the rate law for a second-order reaction can be expressed as: \[ \text{Rate} = k[A]^2 \] Here, \( [A] \) is the concentration of the reactant, and \( k \) is the rate constant.
This means the rate of the reaction is directly proportional to the square of the concentration of the reactant.
For example, if the concentration of \( A \) is doubled, the rate increases by a factor of 4, which is characteristic of a second-order reaction.
Thus, the correct answer is: The square of the concentration of the reactant.