Question

why acetic acid is corrosive and inflammable

Answer 1

The corrosive action of acetic acid on living tissues is due to the catalytic reaction of acid-base in ester and amide hydrolysis. The acetic acid reacts with the skin and hydrolyze the fats which are the chemical forms of esters. Proteins in the skin exist as amides and they are hydrolyzed by acid-base catalysis.
Acetic acid is flammable as it is highly oxidised molecule that itself gets combusted even in slighest heat.