InterviewSolution
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InterviewSolution
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A weak acid `(HA)` after treatment with `12 mL` of `0.1 M` strong base `(BOH)` has a `pH` of `5`. At the end point , the volume of same base required is `27 mL`. `K_(a)` of acid is `(log 2=0.3)`A. `1.8xx10^(-5)`B. `8xx10^(-6)`C. `1.8xx10^(-6)`D. `8xx10^(-5)` |
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Answer» Correct Answer - B mmoles of `HA` taken `=27xx0.1=2.7` `underset(1.5)underset(2.7)(HA)+underset(-)underset(1.2)(OH^(-) )rarr underset(1.2)underset()(A^(-))+H_(2)O` `pH =pK_(a)+log``([A^(-)])/([HA])implies 5=pK_(a)+log``((1.2)/(1.5))` `=pK_(a)+log``(4)/(5)` `:. pK_(a)=5.1 implies K_(a)=80xx10^(-6)` |
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