Problem: Which element is oxidized and which is reduced in the following reactions?N2(g) + 3 H2(g) → 2 NH3(g)

N₂(g) + 3 H₂(g) → 2 NH₃(g)

To do so, we need to identify the change in oxidation state for each element in the reaction. 

Recall the mnemonic for redox reactions:

Loss Electrons → Oxidation → Reducing Agent

Gain Electrons → Reduction → Oxidizing Agent

Reaction: N₂(g) + 3 H₂(g) → 2 NH₃(g)

Reactants:

For N₂: 

This is an atom in its elemental form, which means O.S. of O = 0.

For H₂: 

This is an atom in its elemental form, which means O.S. of O = 0.

Products: