Question

What is the unit of rate constant for a zero-order reaction?

Answer 1

Rate constant

• The equation for rate is as follows:-

$$\begin{gathered} \text{Rate}=k{\left[\text{A}\right]}^{\mathrm{x}}{\left[B\right]}^{\mathrm{y}}......\left(1\right) \\ -\frac{d\left[\text{R}\right]}{dt}=k{\left[\text{A}\right]}^{\mathrm{x}}{\left[B\right]}^{\mathrm{y}}....\left(2\right) \end{gathered}$$

• This form of equation (2) is known as the differential rate equation. Here, k is the rate constant.

Unit of rate constant for zero-order

$$\begin{gathered} k=\frac{\text{Rate}}{{\left[A\right]}^{\mathrm{x}}{\left[B\right]}^{\mathrm{y}}} \\ =\frac{\text{Concentration}}{\text{Time}}\times \frac{1}{{\left[\text{Concentration}\right]}^{\mathrm{n}}} \\ =\frac{{\text{molL}}^{-1}}{\text{s}}\times \frac{1}{{\left[{\text{molL}}^{-1}\right]}^0} \\ ={\text{molL}}^{-1}{\text{s}}^{\text{-1}} \end{gathered}$$

Here, n is the order of the reaction.

So, the unit of rate constant for zero-order is ${\text{molL}}^{\text{-1}}{\text{s}}^{\text{-1}}$.