The γ-radiolysis of p-hydroquinone (H2Q) in deaerated solutions with different solutes is reported. At high pH there is no change in the system. When pH is lowered, H2Q is consumed and G(-H2Q) is pH and H2Q dependent. Small yields of quinone (Q) were observed but G(Q) ∼ 10% of H2Q disappeared. G(−H2Q) is the same in different acids while G(Q) and G(H2O2) depend on the acid used. Competition studies were employed to evaluate the rate coefficient for the reaction of H with H2Q. The values obtained support the reaction mechanism proposed. When N2O is added, Q and 2-hydroxybenzoquinone (2-Q-OH) are produced, and their yields are pH dependent. A reaction mechanism is proposed to explain the experimental observations.