Question

Which of the following aqueous solutions are good buffer systems?

0.13 M calcium hydroxide + 0.25 M calcium bromide

0.27 M ammonia + 0.32 M potassium hydroxide

0.39 M sodium chloride + 0.28 M barium chloride

0.28 M hydrobromic acid + 0.16 M potassium bromide

0.21 M hydrocyanic acid + 0.22 M potassium cyanide

0.34 M nitrous acid + 0.21 M sodium nitrite

0.16 M sodium fluoride + 0.21 M hydrofluoric acid

0.28 M ammonium nitrate + 0.39 M ammonia

0.21 M acetic acid + 0.13 M potassium acetate

0.29 M perchloric acid + 0.24 M potassium perchlorate

Answer 1

Answer :

Good buffer system are those systems (1) combination of weak acid and it's salt with strong base (2) combination of weak base and it's salt with strong acid .

Strong acid or strong base can not make a good buffer system.

(1) : 0.13 M calcium hydroxide + 0.25 M calcium bromide = not a good buffer system since calcium hydroxide is strong base .

(2) : 0.27 M ammonia + 0.32 M potassium hydroxide = not a good buffer since both are bases .

(3) : 0.39 M sodium chloride + 0.28 M barium chloride = not a good buffer system since both are neutral salts .

(4) : 0.28 M hydrobromic acid + 0.16 M potassium bromide = not a good buffer system since hydrobromic acid is strong acid .

(5) : 0.21 M hydrocyanic acid + 0.22 M Potassium cyanide = Good buffer system ( weak acid and it's salt with strong base)

(6) : 0.34 M nitrous acid + 0.21 M sodium nitrite = Good buffer system ( weak acid and it's salt with strong base)

(7) : 0.16 M sodium fluoride + 0.21 M hydrofluoric acid = Good buffer system ( since HF is weak acid and NaF is its salt with strong base)

(8) : 0.28 M ammonium nitrate + 0.39 M ammonia = Good buffer system ( weak base ammonia + it's salt with strong acid ammonium nitrate)

(9) : 0.21 M acetic acid + 0.13 M potassium nitrate = Good buffer system ( weak acid and it's salt with strong base )

(10) : 0.29 M perchloric acid + 0.24 M potassium perchlorate = Not a good buffer system ( since perchloric acid is strong acid)