Question

The gaseous reaction A (g) ¾® 2B (g) + C (g) is found to be first order with respect to A. If the reaction is started with p_A = 90 torr the pressure after 10 min is found to be 180 torr. The rate constant of the reaction is

• A. 1.15 × 10^–3 s^–1
• B. 2.30 × 10^–3 s^–1
• C. 3.45 × 10^–3 s^–1
• D. 4.60 × 10^–3 s^–1

Answer 1

Answer: (A)

1.15 × 10^–3 s^–1

Answer 2

A (g) ¾® 2B(g) + C (g)

P₀ – p 2p p

P_t = P₀ + 2p = 180 torr

p = 45 torr

k = – $\frac{1}{t}$ ln $\frac{45}{90}$ = 1.15 × 10^–3 s^–1