Consider a reversible reaction for which the rates of the forward and reverse reactions vary with time as follows:
Time (min): 0 10 20 30 40
Rate_forward (×10⁻² mol L⁻¹ min⁻¹): 9.0 5.6 4.0 3.2 3.0
Rate_reverse (×10⁻² mol L⁻¹ min⁻¹): 0.0 2.4 3.5 3.2 3.4
At which time does the system first reach equilibrium?
a) 20 min
b) 10 min
c) 30 min
d) 40 min