6 important reaction on acid, bases

i. When an acid reacts with a metal, then a salt and hydrogen gas is formed.

Acid + Metal → Salt + Hydrogen gas

Example - When  dilute  hydrochloric  acid  reacts  with the  metal zinc,  zinc  chloride is  formed  with  the  evolution  of hydrogen gas.

ii. When an acid reacts with a metal carbonate then a salt, carbon dioxide and water are produced.

Example: When dilute hydrochloric acid reacts with sodium carbonate, then sodium chloride, carbon dioxide and water are formed.

iii. 

The reaction between an acid and a base to form salt and water is called a neutralisation reaction.

Base + Acid → Salt + Water

When hydrochloric acid reacts with sodium hydroxide solution, then a neutralisation reaction takes place to form sodium chloride and water.

iv. 

Acids react with metal to form salt and water.

Metal oxide + Acid → Salt + Water

v. Bases react with non-metallic oxides to form salt and water.

For Example: Calcium hydroxide reacts with non-metallic oxides like carbon dioxide to form calcium carbonate salt and water.