Question

Wtrich of the following aqueous solutions are good buffer systems? 0.21 M perchloric acid + 0.21 M sodium perchlorate 20.29 M ammonium nitrate + 0.31 M ammonia 0.19 M calcium hydroxide + 0.21 M calcium bromide 0.40 M acetic acid + 0.22 M potassium acetate 0.10 M nitrous acid + 0.13 M potassium nitrite

Answer 1

A buffer is a solution of weak acid and its conjugate base or vice versa.

A buffer works best when [Acid] $\approx$ [Conjugate base ] or [Base] $\approx$ [Conjugate acid].

So, buffer systems are

b) 0.29 M ammonium nitrate (Conjugate acid) and 0.31 M NH₃ (base).

d) Acetic acid (0.40 M) and its conjugate base (0.22 M potassium acetate ) .

e) 0.10 M nitrous acid (weak acid) + 0.13 M potassium nitrite (conjugate base) .

But in solution d) 0.40 M Acetic acid and 0.22 M potassium acetate concentration of acid and its conjugate base are not close . Hence it is not a good buffer system.

So good buffer system are

Solution b and e .