Chemical reactions of  Acetic acid involve either C-O cleavage or O-H cleavage or both. It undergoes O-H cleavage when it reacts with

In its reaction with PCl5,SOCl2  and NH3/∆ it undergoes C-O cleavage,CH3COCl and CH3CONH2 are formed;CH3-COOH+CH3MgBr →CH4+MgOHBr; In this reaction O-H cleavage of Acetic acid occurs;