InterviewSolution
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InterviewSolution
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Calculate the `pH` of a buffer solution prepared by dissolving `10.6 g` of `Na_(2)CO_(3)` in `500 ml` of an aqueous solution containing `80 ml` of `1 M HCl`. `K_(a)` for `HCO_(3)^(-)=6xx10^(-11)`A. `8.6`B. `9.6`C. `11.6`D. `12.6` |
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Answer» Correct Answer - B `{:(,Na_(2)CO_(3),+,HCl,to,NaCl,+,NaHCO_(3)),("Meq. before",(10.6)/(106)xx1000,,2,,80xx1,,4),("Reaction",=100,,80,,0,,0),("Meq. After",20,,0,,80,,80),("Reaction",1,,2,,2,,2):}` The reaction has `Na_(2)CO_(3)` and `HCO_(3)^(-)` and thus acts as buffer `pH= -logK_(a)+log``([CO_(3)^(-2)])/([HCO_(3)^(-)])` `= -log 6xx10^(-11)+log``(20)/(80)=9.6` |
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