Question

The rate constant for the reaction, $2N_{2}O_{5} \to 4NO_{2} + O_{2}$ is $2 \times 10^{-5} s^{-1}$. If rate of reaction is $1.4 \times 10^{-5} \,mol \, L^{-1} s^{-1}$, what will be the concentration of $N_{2}O_{5}$ in mol $L^{-1}$ ?

• A. $0.8$
• B. $0.7$
• C. $1.2$
• D. $1$

Answer 1

Answer: (B)

Rate $=k[N_{2}O_{5}]$ (first order as unit of rateconstant is $s^{-1}$)
$[N_{2}O_{5}]=\frac{rate}{k}=\frac{1.4\times10^{-5}mol\,L^{-1}\,s^{-1}}{2\times10^{-5} s^{-1}}$
$=0.7 mol \, L^{-1}$