(a)Show graphically how the rate of a first order reaction with only one reactant depends upon the concentration of the reactant.
(b) Give one example of a first order reaction.

(a)

The rate i.e., dx / dt depends on the concentration of the reactant. Let dx / dt = k[A]¹.
On taking log

On plotting log dx / dt versus log A is always a straight line with slope equal to 1.
(b) Example of a first order reaction.
Decomposition of nitrogen pentoxide (N₂O₅)