InterviewSolution
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InterviewSolution
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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 for all practical purpose, but since the ratio `(["Base"])/(["Salt"])` or `(["Salt"])/(["Acid"])` change, a slight decrease or increase in pH results in. A solution containing `0.2` mole of dichloroacetic acid `(K_(a)=5xx10^(-2))` and `0.1` mole sodium dichloroacetate in one litre solution has `[H^(+)]` :A. `0.05M`B. `0.025M`C. `0.10M`D. `0.005M` |
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Answer» Since `{:(CHCl_(2)COONa,rarr ,CHCl_(2)COO^(-),+,Na^(+)),(,,0.1,,0.1),(CHCl_(2).COOH,hArr ,CHCl_(2)COO^(-),+,H^(+)),(0.2,,0,,0),((0.2-x),,(x+0.1),,x):}` `K_(a)=([CHCl_(2)COO^(-)][H^(+)])/([CHCl_(2)COOH])` or `5xx10^(-2)=([0.1+x][x])/([0.2-x])` `:. x=0.05` |
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