Which of the following aqueous solutions are good buffer systems?

0.25 M ammonium nitrate + 0.40 M ammonia

0.23 M nitric acid + 0.20 M sodium nitrate

0.16 M potassium hydroxide + 0.22 M potassium chloride

0.39 M hypochlorous acid + 0.25 M potassium hypochlorite

0.12 M hydrofluoric acid + 0.14 M sodium fluoride

0.25 M ammonium nitrate + 0.40 M ammonia

0.39 M hypochlorous acid + 0.25 M potassium hypochlorite

0.12 M hydrofluoric acid + 0.14 M sodium fluoride

Explanation:

A buffer consists of a weak acid and its salt or a weak base and its salt.

NH₃ is a weak base, and HClO and HF are weak acids.

B is wrong. HNO₃ is a strong acid.

C is wrong. KOH is a strong base.