Question

45 g of ethylene glycol `(C_(2)H_(6)O_(2))` is mixed with 650 g of water. The freezing point depression (in K) will be `(K_(f)"for water "=1.86 "K kg mol"^(-1))`.

Answer 1

Molality of solution (m)
`=("No of moles of "C_(2)H_(6)O_(2))/("Mass of water in kg")`
`=(((45g))/((62" g mol"^(-1))))/(6.65kg)=((0.73 mol))/((0.65kg))=1.12"mol kg"^(-1)`
`DeltaT_(f)=K_(f)xxm=(1.86" K kg mol"^(-1))xx(1.12 "mol kg"^(-1))`
`=2.08 K~~2K.`