Question

The rate constant of a first order reaction is $4\times {10}^{-3}{\sec }^{-1}$ .At a reactant concentration of $0.02M$, the rate of reaction would be:

• A. $8\times {10}^{-5}M{\sec }^{-1}$
• B. $4\times {10}^{-3}M{\sec }^{-1}$
• C. $2\times {10}^{-1}M{\sec }^{-1}$
• D. $4\times {10}^{-1}M{\sec }^{-1}$

Answer 1

The correct option is A $8\times {10}^{-5}M{\sec }^{-1}$

$r=K\left[A\right]$

$=4\times {10}^{-3}\times 0.02$

$=8\times {10}^{-5}M{s}^{-1}$

Hence, the correct option is A.