What is the chemical formula of ammonia gas?

• Ammonia is a chemical compound that is made up of nitrogen and hydrogen atoms.
• Combining capacity(valency) of N and H is 3 and 1 respectively.
• So, one N atom will combine with 3 hydrogen atoms.

The chemical equation for formation of ammonia is:

${\mathrm{N}}_2+3{\mathrm{H}}_2 \rightleftharpoons 2{\mathrm{NH}}_3$

Hence, chemical formula of ammonia is NH₃.