The reaction,$N_2O_5 \longrightarrow 2NO_2 + \frac{1}{2} O_2$ is of first order for $N_2O_5$ with rate constant $6.2 \times 10^{-4} \ s^{-1}$. What is the value of rate of reaction when $[N_2O_5] = 1.25 \ mol \ L^{-1}$?

• A
  $5.15 \times 10^{-5} \ mol \ L^{-1} \ s^{-1}$
• B
  $6.35 \times 10^{-3} \ mol \ L^{-1} \ s^{-1}$
• C
  $7.75 \times 10^{-4} \ mol \ L^{-1} \ s^{-1}$
• D
  $3.85 \times 10^{-4} \ mol \ L^{-1} \ s^{-1}$