Deduce what you can about the nature of the following reactions.

(a) One mole of NH₂OH reacts with two moles of Ti(III) in the presence of excess alkali, and the Ti(III) is converted to Ti(IV).

(b) When Ag₂HPO₃ is warmed in water, all the silver is precipitated as metal.

(c) When one mole of H₃PO₂ is treated with excess I₂ in acidic solution, one mole of I₂ is reduced; on making the solution alkaline, a second mole of I₂ is consumed.