Equilibrium describes the balance that results from a forward and reverse reaction proceeding at equal rates. Since reaction rates depend on concentration, temperature, and pressure, any changes in these conditions may alter the forward and reverse rates unequally and disrupt the equilibrium.

Le Chatelier's principle states that after a change in conditions displaces a reaction from equilibrium

a) the reaction will undergo a temperature change in order to offset the disturbance.

b) the reaction proceeds to a new equilibrium in the direction that offsets the change.

c) the disturbance will always cause the forward reaction to be slower than the reverse reaction.

d) the change in conditions must be reversed in order to regain equilibrium.