What is the effect of adding naoh(aq) to an aqueous solution of ammonia?

1. The pH of the solution will increase.

2. The concentration of NH₄⁺(aq) will decrease.

3. The concentration of NH₃(aq) will increase.

Explanation:

1. The pH of the solution will increase:

As a strong base (NaOH) is added to weak base ammonia.

2. The concentration of NH₄⁺(aq) will decrease.:

According to Le Chatelier’s principle questions. Both ammonia and sodium hydroxide are bases with the former being a weak base and the latter a strong base. When you add ammonia (a gas) to water the equilibrium shown below gets set up:

NH₃(gas) + H₂O = NH₄⁺(aq) + OH⁻(aq)

Now, if you had sodium hydroxide to this you are adding OH-. OH- appears on the right side of the above equation so when you add sodium hydroxide you will cause the equilibrium to shift to the left. The effect will be to force NH3 out of solution and back to the gas form.

3. The concentration of NH₃(aq) will increase.

As the reaction is shifted to  the left (reactants side).