A solution of `x` moles of sucrose in `100`grams of water freeze at `-0.2^(@)C` As. Ice separates the freezing point goes down to `0.25^(@)C`. How many grams of ice would have separated ?

Options

A. 18 grams
B. 20 grams
C. 25 grams
D. 23 grams

Answer

B

Explanation

`DeltaT_(f) = m xx K_(f)`
`0.2 xx (X xx 1000)/100 xx 1.86 " " X = (0.2)/(10 xx1.86)`
after freezing
`DeltaT_(f) = m xx K_(f)`
`DeltaT_(f) = m xx K_(f)`
`DeltaT_(f) = (X xx 1000)/((100 -y)) xx 1.86 " " DeltaT_(f) = 0.25`
On solving ,Amount of ice y = 20 g ice