Here's how to determine the net ionic equation for the reaction of hydrobromic acid (HBr) and ammonia (NH₃):

1. Write the balanced molecular equation:

HBr(aq) + NH₃(aq) → NH₄Br(aq)

2. Write the complete ionic equation:

H⁺(aq) + Br⁻(aq) + NH₃(aq) → NH₄⁺(aq) + Br⁻(aq)

3. Identify the spectator ions:

Spectator ions are ions that appear on both sides of the equation and do not participate in the reaction. In this case, Br⁻ is the spectator ion.

4. Write the net ionic equation:

H⁺(aq) + NH₃(aq) → NH₄⁺(aq)

Therefore, the net ionic equation for the reaction of hydrobromic acid and ammonia is:

H⁺(aq) + NH₃(aq) → NH₄⁺(aq)