The differential rate law for the reaction $\mathrm{H}_2+\mathrm{I}_2 \rightarrow 2 \mathrm{HI}$ is

• A

  $-\frac{\mathrm{d}\left[\mathrm{H}_2\right]}{\mathrm{dt}}=-\frac{\mathrm{d}\left[\mathrm{I}_2\right]}{\mathrm{dt}}=-\frac{\mathrm{d}[\mathrm{HI}]}{\mathrm{dt}}$
• B

  $\frac{\mathrm{d}\left[\mathrm{H}_2\right]}{\mathrm{dt}}=\frac{\mathrm{d}\left[\mathrm{I}_2\right]}{\mathrm{dt}}=\frac{1}{2} \frac{1 \mathrm{~d}[\mathrm{Hl}]}{\mathrm{dt}}$
• C

  $\frac{1}{2} \frac{\mathrm{d}\left[\mathrm{H}_2\right]}{\mathrm{dt}}=\frac{1}{2} \frac{\mathrm{d}\left[\mathrm{I}_2\right]}{\mathrm{dt}}=-\frac{\mathrm{d}[\mathrm{HI}]}{\mathrm{dt}}$
• Correct answer
  D

  $-2 \frac{\mathrm{d}\left[\mathrm{H}_2\right]}{\mathrm{dt}}=-2 \frac{\mathrm{d}\left[\mathrm{I}_2\right]}{\mathrm{dt}}=\frac{\mathrm{d}[\mathrm{HI}]}{\mathrm{dt}}$

Hence, the correct answer is option: 'D'.