What should be the freezing point of aqueous solution containing `17g` of `C_(2)H(5)OH` is `1000g` of water (`K_(f)` for water =`1.86 deg kg mol^(-1)`)?

Options

A. 272.31 K
B. 273.69 K
C. 272 K
D. 27.36 K

Answer

A

Explanation

`Delta T_(f) = (1000 xx K_(f) xx W_(2))/(M_(2) xx W_(1))=(1000 xx 1.86 xx 17)/(46 xx 1000)=0.69^(@)C`
`Delta T_(f) = T_(f)^(@) - T_(f)`
`:. T_(f) = Delta T_(t) - T_(f)^(@) = 0 -0.69 = - 0.69^(@)C`
`= - 0.69^(@)C + 273 = 272.31 K `