Question

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

• A. \(\text{s}^{-1}\)
• B. \(\text{mol}^{-2}\text{ dm}^6\text{ s}^{-1}\)
• C. \(\text{mol dm}^{-3}\text{ s}^{-1}\)
• D. \(\text{mol}^{-1}\text{ dm}^3\text{ s}^{-1}\)

Hint:

Divide the units of rate by the square of concentration units.

Answer 1

The Correct Option is D

Step 1: Rate=k[A]^2.

Step 2: k = Rate/[A]^2 = (mol dm-3 s-1)/(mol dm-3)^2.

Step 3: k = mol-1 dm3 s-1.

\[\boxed{k = \text{mol}^{-1}\text{ dm}^3\text{ s}^{-1}}\]