# Are all hydrolysis reactions non-redox reactions? [closed]

Are all hydrolysis reactions always non redox reactions? For example:

$$\ce{N2O3 + 2H2O -> 2HNO2}$$

The main reason I say that this statement is correct is because oxygen and hydrogen generally show oxidation states of −2 and +1 respectively when bonded to other atoms.

This means that any change in oxidation state needs to take place between the nitrogen atoms involved in the molecular structure and this is very rarely seen.

Hence most (if not all) hydrolysis reactions are non-redox in nature. Is there a mistake in my understanding?

• Well, that would depend on what's you'll call hydrolysis - I wouldn't call reactions of oxides with water like that. – Mithoron May 26 at 16:17
• Hydration is sure different then hydrolysis, like, an opposite. – Mithoron May 26 at 16:47
• Exception: Hydrolysis of phosphorus pentachloride – Nilay Ghosh May 27 at 3:49

$$\ce{Mg2\overset{-4}{Si} + 4\overset{+1}{H}_2O -> 2Mg(OH)2 + \overset{+4}{Si}\overset{-1}{H}_4}$$
No. One counter example for the proposed statement would be the case of hydrolysis of dinitrogen tetroxide: $$\ce{N2O4 + H2O -> HNO2 + HNO3}$$ Here, the nitrogen goes from a $$+4$$ state to a $$+3$$ and $$+5$$ in nitrous acid and nitric acid, respectively.