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Calculate the molarity of a solution of ethnol in water in which the mole fraction of ethanol is `0.040`. |
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Answer» `chi_(C_(2)H_(5)OH)=(n(C_(2)H_(5)OH))/(n(C_(2)H_(5)OH)+n(H_(2)O))=0.040` (Given) …(i) The aim is to find number of moles of ethnol in `1 L` of the solution which is nearly `=1 L` of water (because solution is dilute) Number of moles in `1 L` of water `=(1000 g)/(18 g mol^(-1))` `=55.55` moles Substituting `n(H_(2)O)=55.55` in equation (i) we get `(n(C_(2)H_(5)OH))/(n(C_(2)H_(5)OH)+55.55)=0.040` or `0.96 n(C_(2)H_(5)OH)=55.55xx0.040` or `n(C_(2)H_(5)OH)=2.31` Hence, molarity of the solution`=2.31 M` |
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