A solution of sucrose (molar mass =342 g `mol^(-1)`) has been prepared by dissolving 68.5 g of sucrose in 100 g of water. The freezing point of the so
A solution of sucrose (molar mass =342 g `mol^(-1)`) has been prepared by dissolving 68.5 g of sucrose in 100 g of water. The freezing point of the solution obtained will be `(K_(f) "for water =1.86 K kg " mol^(-1))`:
A. `-0.372^(@)C`
B. `-0.52^(@)C`
C. `+0.372^(@)C`
D. `-0.57^(@)C`
4 views
1 Answers
Correct Answer - a
Molality (m) of solution
`=("Mass of solute 1 kg of solvent")/"Molar mass"`
`=((68.5g)//(1kg))/((342gmol^(-1)))=0.2 mol//kg`
`DeltaT_(f)=K_(f)xxm`
` =(1.86 K kg mol^(-1))xx(0.2 mol//kg^(-1))`
f.p. of solution =`(0-0.372)=-372^(@)C`.
4 views
Answered