Question

Nitrogen gas (N2) and hydrogen gas (H2) combine to form ammonia (NH3). Which equation correctly represents this reaction?

A.
N + H → NH

B.
2N2+ H2 → 3NH3

C.
2NH → N + 3H2

D.
N2+ 3H2 → 2NH3

Answer 1

If this is a balance the equation question, the answer is the one that has equal numbers of each type of element on both sides of the equation.
Nitrogen and Hydrogen are both diatomic molecules if i recall correctly. They exist in pairs as given in the question.

Given: N2 + H2 --> NH3

You need to add coefficients in order to make each side have the same number of hydrogen and nitrogen atoms.