Consider the reversible gas-phase reaction 2NO2(g)⇌N2O4(g) carried out in a closed cylinder at constant temperature. Four students make the following claims about the reaction mixture after 3 minutes.
Which student’s claim indicates that the reaction mixture has NOT yet reached equilibrium?
a) Only N2O4 is present, so the system is at equilibrium.
b) The forward rate is greater than the reverse rate, and the partial pressure of NO2 is still decreasing.
c) The forward rate equals the reverse rate, so the partial pressures are no longer changing.
d) The partial pressures of NO2 and N2O4 are equal, so the reaction has reached equilibrium.