InterviewSolution
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InterviewSolution
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Which solutionwill have pH closer to `1.0` ?A. `75 mL` of `M//5HC1 + 25 mL` of `M//5 NaOh`B. `10mL` of `M//10 HC1 + 90 mL` of `M//10 NaOH`C. `55mL` of `M//10 HC1` + `54mL` of `M//10 NaOH`D. `100 mL` of `M//10 HC1 + 100 mL` of `M//10 NaOH` |
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Answer» Correct Answer - A a.mmol of `HC1 = 75 xx (1)/(5) = 15` mmol of `NaOH = 25 xx (1)/(5) = 5` mmol of HC1 left `= 15 - 5 = 10` Volume `= 75 + 25 = 100` `[H^(o+)] = (10)/(100) = 0.1 = 10^(-1)M` `pH = 1` b. mmol of `HC1 = 10 xx (1)/(10) = 1` mmol of `NaOH = 90 xx (1)/(10) = 9` mmol of `NaOH` left `= 9 - 1 = 8` Since base is left, `:. pH gt 7` c. mmol of `HC1 = 55 xx (1)/(10) = 5.5` mmol of `NaOH = 45 xx (1)/(10) = 4.5` mmol of `HC1` left `= 5.5 - 4.5 = 1.0` Volume `= 55 + 45 = 100` `[H^(o+)] = (1)/(100) = 10^(-2)` `pH = 2` d. mmol of `HC1 = 100 xx (1)/(10) = 10` mmol of `NaOH = 100 xx (1)/(10) = 10` Both `S_(A)` and `S_(B)` are neutralised. `:. pH = 7`. |
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