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`30mL` of `CH_(3)OH (d = 0.780 g cm^(-3))` and `70 mL` of `H_(2)O (d = 0.9984 g cm^(-3))` are mixed at `25^(@)C` to form a solution of density `0.9575 g cm^(-3)`. Calculate the freezing point of the solution. `K_(f)(H_(2)O)` is `1.86 kg mol^(-1)K`. Also calculate its molarity. |
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Answer» Correct Answer - `-19.91^(@)C, 7.63M` `CH_(3) OH rarr V_(1) = 30 mL, d_(1) = 0.798 g//mL` `m_(1) = 23.94 g` `H_(2)O rarr V_(2) = 70 mL, d_(2) = 0.9984 g//mL` `m_(2) = 69.888g` `m_(T) = 93.828g` `d_("solution") = 0.9575 g//mL` `V_("solution") = 98 mL` `DeltaT_(f) = (1.86 xx 23.94 xx 1000)/(32xx 69.888) = 19.91` `T_(f) =- 19.91^(@)C` `M = (23.94)/(32 xx 0.98) = 7.63M` |
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