Dear Student,
Acetic acid (CH3COOH) is acid and Sodium hydroxide (NaOH) is base or alkali.
Acetic acid neutralises sodium hydroxide base to form salt of sodium acetate and this reaction also generate water.
CH3COOH (aq) + NaOH(aq) CH3COO-Na (aq) + H2O(aq)
sodium acetate
This type of reaction is called as acid-base neutralisation reaction.
Regards,