Question

The unit of velocity (rate) constant for a second-order reaction is:

• A. \( \text{litre mol}^{-1} \text{second}^{-1} \)
• B. \( \text{litremol}\text{second}^{-1} \)
• C. \( \text{litre}\text{second}^{-1} \)
• D. \( \text{litre mol} \text{second}^{-1} \)

Hint:

The unit of the rate constant depends on the order of the reaction.

Answer 1

The Correct Option is A

For a second-order reaction, the rate law is: \[ \text{Rate} = k[A][B]. \] The unit of \( k \) is: \[ \frac{\text{Rate}}{\text{Concentration}^2} = \frac{\text{mol litre}^{-1} \text{second}^{-1}}{(\text{mol litre}^{-1})^2} = \text{litre mol}^{-1} \text{second}^{-1}. \]