InterviewSolution
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InterviewSolution
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The addition of `3g` of a substance to `100g C CI_(4)(M = 154 g mol^(-1))` raise the boiling point of `C CI_(4)` by `0.60^(@)C` of `K_(b)(C CI_(4))` is `5.03 kg mol^(-1) K`. Calculate: (a) the freezing point depression (b) the relative lowering of vapour pressure (c) the osmotic pressure at `298K` the molar mass of the substance Given `K_(f)(C CI_(4)) = 31.8 kg mol^(-1) K` and `rho` (density) of solution `= 1.64g//cm^(3)` |
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Answer» Correct Answer - (a) `3.793^(@)C` (b) `0.018`, (c) `4.65 atm`, (d) `251.5` (a) `(Delta T_(t))/(Delta T_(b)) = (k_(f))/(k_(b))=Delta T_(f)=(0.6xx31.8)/(5.03)=3.793^(@)C` (b) Relative lowering of vapour pressure = `(n)/(n+N)=((3)/(251.5))/((3)/(251.5)+(100)/(154))=0.018` (c ) `pi = CRT` `n = (3)/(251.5)=0.012` `v = (103)/(1.64) = 62.8 mL` `pi = (0.012)/(0.0628)xx0.0821xx298=4.65` atm (d) `0.6 = (5.03xx3xx1000)/(M_(W)xx100) = gt M_(W) = 251.5` |
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