Which of the following can be used to neutralize an ammonia (NH3) solution?

NaCl

H2O

HNO3

Ca (OH) 2

NH3 forms a basic solution of ammonium hydroxide.

NaCL - no it is a salt. Salts are generally inert.

H2O - no, it is both an acid and base, but because of this it has neutralized itself and is also inert.

HNO3 - yes. It is a strong acid and forms the salt ammonium nitrate.

Ca (OH) 2 - no, it is another base. Bases react with acids.

your answer is HNO3