The molecular formula of ammonia is:

1. NO
2. NH₃
3. NO₂
4. N₂O

NH₃

Reason — Ammonia is made up of nitrogen and hydrogen. The valency of nitrogen is 3 and valency of hydrogen is 1.

$\overset{\phantom{3}{3}}{\text{N}} \space {\swarrow}\mathllap{\searrow} \space \overset{1}{\text{H}} \Rightarrow \underset{\phantom{1}{1}}{\text{N}} \space {\swarrow}\mathllap{\searrow} \underset{\phantom{3}{3}}{\text{H}} \\[1em] \text{N}\text{H}_3$