A substance reacts according to first-order kinetics. The rate constant for the reaction is 1 x 10^–2 sec^-1. Its initial concentration is 1M. Its initial rate is:

1 × 10^–2 Ms^–1

The correct answer is option 3. 1 × 10^–2 Ms^–1.

To determine the initial rate of a reaction, we can use the first-order rate equation:

\(\text{Rate} = k[A] \)

where \(\text{Rate}\) is the rate of the reaction, \(k\) is the rate constant, and \([A]\) is the concentration of the reactant.

Given that the rate constant (\(k\)) is \(1 \times 10^{-2} \, \text{sec}^{-1}\) and the initial concentration (\([A]_0\)) is \(1 \, \text{M}\), we can substitute these values into the rate equation to find the initial rate (\(\text{Rate}_0\)):

\(\text{Rate}_0 = k \times [A]_0 \)

\(\text{Rate}_0 = (1 \times 10^{-2} \, \text{sec}^{-1}) \times (1 \, \text{M}) \)

\(\text{Rate}_0 = 1 \times 10^{-2} \, \text{M/sec} \)

Therefore, the correct answer is \((3) \, 1 \times 10^{-2} \, \text{Ms}^{-1}\).