Which chemical equation correctly represents the reaction that takes place when nitrogen gas and hydrogen gas are formed as ammonia decomposes?

N (g) + H3 (g) → NH3 (g)

2N (g) + 3H2 (g) → 2NH3 (g)

2NH3 (g) → N2 (g) + 2H3 (g)

2NH3 (g) → N2 (g) + 3H2 (g

2NH3 (g) → N2 (g) + 3H2 (g

Explanation:

Let us write a balanced equation for the decomposition of NH3. This is illustrated below:

NH3 → N2 + H2

Next, let us balance the equation.

There are 2 atoms of N on the right side and 1 atom on the left side. It can be balance by putting 2 in front of NH3 as shown below:

2NH3 → N2 + H2

Now, we see that there are 6 atoms of H on the left side and 2 atoms on the right side. It can be balance by putting 3 in front of H2 as shown below:

2NH3 → N2 + 3H2