InterviewSolution
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InterviewSolution
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How much `C_(2)H_(5)OH` must be added to `1.0"L of "H_(2)O`, so that solution should not freeze at `-4^(@)F` ? `[K_(f)(C_(2)H_(5)OH)=1.86^(@)C//m]`A. `lt10.75g`B. `gt494.5g`C. `lt20g`D. `494.5g` |
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Answer» Correct Answer - B `(C)/(5)=(F-32)/(9)` `-4^(@)F=-20^(@)CrArrDeltaT_(f)=20^(@)C` `"From "DeltaT_(f)=K_(f).mrArrm=(20)/(1.86)=10.75m` `"Mass of "C_(2)H_(5)OH" needed "=10.75xx46=494.5g` Solution not to freeze at `-20^(@)C` will require more ethanol than the mass needed to freeze at `-20^(@)C`. |
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