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Heat of dissociation of acetic acidis 0.30 kcal`mol^(-1)` . Hence,enthalpy change when 1 mol of`Ca(OH)_(2)` is completely neutralized by acetic acid would beA. `-13.4 kcal`B. `-27.1 kcal`C. `-26.8 kcal`D. `-27.4 kcal` |
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Answer» Correct Answer - c `Ca(OH)_(2) rarr Ca^(2+) + 2OH^(-) , i.e., 1` mole of`Ca(OH)_(2)` gives two moles of `OH^(-)` ions. Hence, when `Ca(OH)_(2)` is completely neutralized,heat produced `= 2 xx 13.7 kcal = 27.4 kcal` 2 moles of `OH^(-)` ions require 2 moles of `H^(+)` ions for complete neutralization. Heat of dissociation of acetic acidto produce 2 moles of`H^(+)` ions `= 2 xx 0.30 kcal = 0.6 kcal`. Hence, net heat produced `=27.4 - 0.6 =26.8 kcal, i.e., DeltaH = - 26.8 kcal` |
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