InterviewSolution
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InterviewSolution
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On the basis of the equation `ph=-log[H^(+)]`,the ph of `10^(-8)` mol `dm^(-3)` solution of HCI should be 8. However, it is observed to be less than 7.0. Explain the reason. |
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Answer» The pH of an acidic solution cannot be more than 7.0. whrneas the expected Ph is 8. To explain this it is suggested that `H^(+)` or `H_(3)O^(+)` ions are also released by the self ionisation of water. Since water is neutral, `[H_(3)O^(+)]=10^(-7)M`. `" therefore Total " [H_3O^(+)]" in solution "=10^(-8)M+10^(-7)M=10^(-8)[1+10]=11xx10^(-8)M` `ph=-log[H_3O^(+)]=-[11xx10^(-8)]=[8-log11]` `ph=[8-1.0411]=6.9586=6.96`. |
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