Ionic EquilibriumHard
Question
Buffer solutions have constant acidity and alkalinity because
Options
A.these give unionised acid or base on reaction with added acid or alkali
B.acids and alkalies in these solutions are shielded from attack by other ions
C.they have large excess of H+ or OH- ions-
D.they have fixed value of pH
Solution
If small amount of an acid or alkali is added to a bufer solution, it converts them into unionised acid or base. Thus, its pH remains unaffected or in other words its acidity/alkalinity remains constant. e.g.,
H3O- + A- ⇋ H2O + HA
-OH + HA → H2O + A-
If acid is added, it reacts A- with to form undissociated HA. Similarly, if base/alkali is added, OH- combines with HA to give H2O and A- and thus, maintanes the acidity/alkalinity of buffer solution.
H3O- + A- ⇋ H2O + HA
-OH + HA → H2O + A-
If acid is added, it reacts A- with to form undissociated HA. Similarly, if base/alkali is added, OH- combines with HA to give H2O and A- and thus, maintanes the acidity/alkalinity of buffer solution.
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