First order gas phase reaction A → B + C p_i= initial pressure of gas A, p_t= total pressure of the reaction mixture at time t Expression of rate…

First order gas phase reaction $$\mathrm{A} \rightarrow \mathrm{~B}+\mathrm{C} $$ $\displaystyle p_i=$ initial pressure of gas A, $\displaystyle p_t=$ total pressure of the reaction mixture at time $\displaystyle t$ Expression of rate constant $\displaystyle (\mathrm{k})$ is