A solution containing 0.45 g of a urea in 22.5 g of water gave a boiling point elevation of 0.17 K. Calculate the molal elevation constant of water. Molar mass of urea is 60 g `"mol"^(-1)`.

Explanation

We are given that
`DeltaT_(b)=0.17KrArrw_(A)=g`
`w_(B)=0.45grArrM_(B)=60"g mol"^(-1)`
We are to find out the molal elevation constant of water, i.e., `K_(b)=?`
`K_(b)=(DeltaT_(b)xxw_(A)xxM_(B))/(w_(B)xx1000)rArrK_(b)=(0.17xx22.5xx60)/(0.45xx1000)`
`K_(b)=0.51`
`therefore` The molal elevation constant of water is 0.51 K `mol^(-1)`.