Question

Which of the following aqueous solutions are good buffer systems? . 0.32 M calcium chloride + 0.27 M sodium chloride 0.35 M ammonia + 0.36 M calcium hydroxide 0.19 M barium hydroxide + 0.28 M barium chloride 0.12 M hydrofluoric acid + 0.17 M potassium fluoride 0.20 M hydrobromic acid + 0.22 M sodium bromide

Answer 1

Answer:

0.12 M hydrofluoric acid + 0.17 M potassium fluoride

Explanation:

To make a buffer, you must to have an aqueous mixture of a weak acid and its conjugate base or vice versa.

Knowing that:

0.32 M calcium chloride + 0.27 M sodium chloride: is not a good buffer system because CaCl₂ and NaCl are both salts.

0.35 M ammonia + 0.36 M calcium hydroxide is not a good buffer system because ammonia is a weak base but calcium hydroxide is a strong base

0.19 M barium hydroxide + 0.28 M barium chloride is not a good buffer system because Ba(OH)₂ is a strong base.

0.12 M hydrofluoric acid + 0.17 M potassium fluoride is a good buffer system because HF is a weak acid and KF (F⁻ in aqueous medium), is its conjugate base

0.20 M hydrobromic acid + 0.22 M sodium bromide is not a good buffer system because HBr is a strong acid.