Identify the expression for average rate for following reaction. $\mathrm{N}_{2(\mathrm{~g})}+3…

Identify the expression for average rate for following reaction. $\mathrm{N}_{2(\mathrm{~g})}+3 \mathrm{H}_{2(\mathrm{~g})} \rightarrow 2 \mathrm{NH}_{3(\mathrm{~g})}$
  1. $\frac{-\Delta\left[\mathrm{N}_2\right]}{\Delta \mathrm{t}}=-\frac{1}{3} \frac{\Delta\left[\mathrm{H}_2\right]}{\Delta \mathrm{t}}=\frac{1}{2} \frac{\Delta\left[\mathrm{NH}_3\right]}{\Delta \mathrm{t}}$
  2. $-\frac{1}{3} \frac{\Delta\left[\mathrm{N}_2\right]}{\Delta \mathrm{t}}=\frac{\Delta\left[\mathrm{H}_2\right]}{\Delta \mathrm{t}}=\frac{1}{2} \frac{\Delta\left[\mathrm{NH}_3\right]}{\Delta \mathrm{t}}$
  3. $\frac{-\Delta\left[\mathrm{N}_2\right]}{\Delta \mathrm{t}}=\frac{-\Delta\left[\mathrm{H}_2\right]}{\Delta \mathrm{t}}=\frac{\Delta\left[\mathrm{NH}_3\right]}{\Delta \mathrm{t}}$
  4. $-\frac{1}{2} \frac{\Delta\left[\mathrm{N}_2\right]}{\Delta \mathrm{t}}=\frac{-\Delta\left[\mathrm{H}_2\right]}{\Delta \mathrm{t}}=\frac{1}{3} \frac{\Delta\left[\mathrm{NH}_3\right]}{\Delta \mathrm{t}}$

Solution

In the rate expression, always make sure to express the rates with the correct sign: Negative for the reactants and positive for the products.

Asked in: MHT CET 2023 (11 May Shift 2)

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