Question

The rate constant of a reaction is 0.005 molL-1 s-1. what is the order of this reaction?

Answer 1

Answer:

The order of the reaction which has a value of rate constant $0.005\ mol\ L^{-1}\ s^{-1}$ is zero order·

Explanation:

The order of a reaction can be defined as the ''sum of the powers of the concentration of reactants in the expression of rate law''· It can be found out from the unit of the rate constant value· It is the sum of the powers of the concentration of reactants in the expression of rate law· According to that, the order of the reaction can be $0\ ,\ 1\ ,\ 2\ ,\ 3\ ,$ and even a fraction·

For a reaction,

aA $+$ bB $--->$ cC $+$ dD

The rate constant,

       K    $=$     $\frac{rate}{[A]^{a}\ [B]^b }$

where,

a and b are the stoichiometric coefficients of the reactant A and B·

The unit can be,

       K     $=$    $\frac{concentration}{time}$ × $\frac{1}{(concentration)^n}$

where,

n = the order of the reaction

The SI unit for the concentration $= mol\ L^{-1}$

The SI unit for time $=$ s

If,

   n  $=$  $0$,  the unit of k  $=$  $mol\ L^{-1} \ s^{-1}$

   n  $=$  $1$,  the unit of k  $=$  $s^{-1}$

   n  $=$  $2$,  the unit of k  $=$  $mol^{-1\ } L\ s^{-1}$

Here,

The value of rate constant is,

   k  $=$  $0.005\ mol\ L^{-1}\ s^{-1}$

The unit is $mol\ L^{-1}\ s^{-1}$·

So it is a zero-order reaction·