Question

The reaction; $N_2{O}_5\left(g\right)⟶2N{O}_2\left(g\right)+\frac{1}{2}{O}_2\left(g\right)$ is of first order for $N_2{O}_5$ with rate constant $6.2\times {10}^{-4}{s}^{-1}$. What is the value of rate of reaction when $\left[N_2{O}_5\right]=1.25mol{L}^{-1}$?

• 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. $3.85\times {10}^{-4}mol{L}^{-1}{s}^{-1}$

Answer 1

Answer: (C)

$7.75\times {10}^{-4}mol{L}^{-1}{s}^{-1}$

As we know,
$r=K\left[N_2{O}_5\right]=6.2\times {10}^{-4}\times 1.25=7.75\times {10}^{-4}mol{L}^{-1}{s}^{-1}$.