The reaction $N_2O_5$ (in $CCl_4$ solution) $\to 2NO_2$ (solution) $+ \frac{1}{2}O_{2(g)}$ is of first order in $N_2O_5$ with rate constant $6.2 \times 10^{-1} \, s^{-1}$. What is the value of the rate of reaction when $[N_2O_5] = 1.25 \, mol \, L^{-1}$?

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