Question

For a reaction the unit of rate constant is sec${}^{-1}$. What will be the order of reaction?

Answer 1

For nth order reaction, Rate $=k[A{]}^n$
The unit of rate is M/s and the unit of [A] is M. Hence, the unit of rate constant k is $M^{(1-n)}/s$
For the given reaction, the unit of rate constant is /s.
$M^{(1-n)}/s=/s$
$M^{(1-n)}=M^0$
$1-n=0$
$n=1$
Hence, the reaction is of first order.