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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_(1) + log.(["Salt"])/(["Acid"])`. Addition of little acid or base although shows no change in pH for all practical purposes , but since the ratio `(["Base"])/(["Salt"])` for `(["Salt"])/(["Acid"])` changes, a slight decrease or increase in pH results. A solution containing 0.2 mole of dichloroacetic acid litre solution has `[H^(+)]`A. 0.05 MB. 0.025 MC. 0.10 MD. 0.005 M |
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Answer» Correct Answer - A Since `CHCl_(2).COOH` is relatively strong acid having more `K_(a)`. `{:(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 `5 xx 10^(-2) = ([0.1 + x][x])/([0.2 - x])` `:. x = 0.05`. |
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