The Ph of basic buffer mixtures is given by : `Ph=Pk_(a)+`log `(["Base"])/(["Salt"])` whereas Ph of acidic buffer mixtures is given by : Ph =`pK_(a)+"log"(["Salt"])/(["Acid"])`. Addition of little acid or base although shows no appreciable change in Ph for all practical purposes, but sicne the ratio `(["Base"])/(["Salt"])` or `(["Salt"])/(["Acid"])` changes, a slight decrease or increase in pH results.
A solution containing 0.2 mole of dichloroacetic acid `(K_(a)=5xx10^(-2))` and 0.1 mole sodium dichloracetate in one litre solution has `[H^(+)]`:

Options

A. 0.05 m
B. 0.025 m
C. 0.10 m
D. 0.005 m

Answer

a