Question

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

Answer 1

Correct Answer - B
`Delta T_(f)=K_(f)xxm`
`Delta T_(b)=K_(b)xxm`
`(Delta T_(f))/(Delta T_(b))=(K_(f))/(K_(b))`
`Delta T_(b) = (Delta T_(f)xxK_(b))/(K_(f))`
`= (0.186xx0.521)/(1.86)=0.0521`