Question

Any chemical reaction which produces gas

Answer 1

Carbondioxide such as oxygen this is the answer

Answer 2

Heya friend,

There are some reaction in which one of the produced product is gas. Such reaction can be acid-base reaction.

One of the reaction in which gas is evolved is replacement reaction of zinc and hydrogen chloride-:

Zn + 2 HCl → ZnCl2 + H2 (gas)

[The '2' after ZnCl and H will be at the bottom]

In this reaction hydrogen gas is produced. There are many other reactions like this,

Hope this answer helped you!