Question

After adding non-volatile solute, freezing point of water decreases to-`0.186^(@)C`. Calculate ` DeltaT_(b)"if " K_(f)=1.86 "K kg mol"^(-1) "and" K_(b)=0.521"K kg " mol^(-1)`.
A. 0.0521 K
B. 0.0186 K
C. 0.521 K
D. 1.86 K

Answer 1

Correct Answer - a
`DeltaT_(f)=K_(f)xxm,DeltaT_(b)xx=K_(b)xxm`
`(DeltaT_(f))/(DeltaT_(b))=K_(f)/K_(b)or DeltaT_(b)=(DeltaT_(f)xxK_(b))/(k_(f))`
`DeltaT_(b)=((0.186K)xx0.521K kg mol^(-1))/((186 K kg mol^(-1)))=0.0521 K`