CHEMISTRY · Single correct · A Level · Chemistry · Chemical equilibria (Le Chatelier’s principle and Kc) · Chemical equilibria (Le Chatelier’s principle and Kc)
Problem
For the reversible reaction C ⇌ D, the following instantaneous rates were obtained.
Time (s) | Rate_forward (mol·L⁻¹·s⁻¹) | Rate_reverse (mol·L⁻¹·s⁻¹)
0 | 1.20 | 0.00
20 | 0.90 | 0.30
40 | 0.65 | 0.55
60 | 0.50 | 0.70
80 | 0.40 | 0.80
100 | 0.35 | 0.85
Which statement best characterizes the overall direction of net conversion during the 0–100 s interval?
(a) Net forward conversion until 60s, equilibrium at 60s, then net reverse conversion thereafter.
(b) Net forward conversion until 40s, equilibrium at 40s, then net reverse conversion thereafter.
(c) Net reverse conversion begins at 20s when the reverse rate first becomes non-zero and continues through 100s.
(d) Net forward conversion until 20s, equilibrium at 20s, then net reverse conversion thereafter.