The molarity of urea (molar mass 60 g `mol^(-1)`) solution by dissolving 15 g of urea in 500 `cm^(3)` of water is

Options

A. `2"mol dm"^(-3)`
B. `0.5"mol dm"^(-3)`
C. `0.125"mol dm"^(-3)`
D. `0.0005"mol dm"^(-3)`

Answer

B

Explanation

Given, mass of urea = 15 g
Molar mass urea `=60gmol^(-1)`
volume `=500cm^(3)=500mL=0.5L`
`{:[(because1cm^(3)=1mL),(1L=1000mL)]:}`
`:.` Molarity
`=("Mass of solute in grams")/("Molar mass of solute "(M)xx"Volume of solution V(L)")`
Molarity of urea `=(15g)/(60gmol^(-1)xx0.5L)`
`rArr" "0.5mol//L=0.5mol//dm^(3)(because1L=1dm^(3))`