Question

Gaseous N₂O₅ decomposes according to the following equation :

N₂O₅(g) ® 2NO₂(g) + $\frac{1}{2}$ O₂(g)

The experimental rate law is –D[N₂O₅]/Dt = k[N₂O₅]. At a certain temperature the rate constant is k = 5.0 x 10^–4/sec. In how seconds will the concentration of N₂O₅ decrease to one-tenth of its initial value?

• A. 2.0 × 10³ s
• B. 4.6 × 10³ s
• C. 2.1 × 10² s
• D. 1.4 × 10³ s

Answer 1

Answer: (B)

4.6 × 10³ s

Answer 2

t = $\frac{2.303}{5 \times 10^{–4}}$ log $\frac{A_{0}}{A_{0}/10}$= 4.6 ×10³ sec