The molality of a urea solution in which ` 0.0100 g ` of urea, ` [(NH_(2))_(2)CO] ` is added to ` 0.3000 dm^(3) `of water at STP is

Options

A. ` 0. 555 m`
B. ` 5.55 xx 10^(-4) m`
C. ` 33.3 m`
D. ` 3.33 xx 10^(-2) m`

Answer

B

Explanation

Molality `=("moles of solute")/("kg of water")`
Moles of unrea` =(0.010)/(60) mol`
Water at `STP (d=1 g/cm^(3) =1 kg//dm^(3)) =0.3 dm^(3) =0.3 kg`
` :.` Molality `=(0010)/(60xx0.3) =5.555 xx10^(-4) m`.