In: Chemistry
Which of the following aqueous solutions are good buffer systems?
0.33 M nitrous acid + 0.27 M potassium nitrite
0.24 M nitric acid + 0.23 M sodium nitrate
0.32 M ammonium nitrate + 0.33 M ammonia
0.16 M hypochlorous acid + 0.12 M sodium hypochlorite
0.16 M potassium fluoride + 0.28 M hydrofluoric acid
Acidic buffer solution is formed by mixing a weak acid and its salt of strong base i.e. its conjugate base.
Basic buffer solution is formed by mixing a weak base and its salt of strong acid i.e. its conjugate acid.
Therefore,
The good buffer solutions are :
(a). 0.33 M nitrous acid + 0.27 M potassium nitrite, Because, HNO2 is a weak acid and potassium fluoride i.e. NO2- is its conjugate base which form a acidic buffer solution.
(b). 0.32 M ammonium nitrate + 0.33 M NH3 , Because, NH3 is a weak base and ammonium nitrate i.e. NH4+ is its conjugate base which form a basic buffer solution.
(c). 0.16 M hypochlorous + 0.12 M sodium hypochlorite, Because, HClO is a weak acid and sodium hypochlorite i.e. ClO- is its conjugate base which form a acidic buffer solution.
(d). 0.16 M potassium fluoride + 0.28 M hydrofluoric acid, Because, HF is a weak acid and potassium fluoride i.e. F- is its conjugate base which form a acidic buffer solution.
On the other hand, HNO3 is the strong acidic therefore not form a buffer solution.