What is the molality of solution containing 200 mg of urea `("molar mass "60"g mol"^(-1))` dissolved in 40 g of water ?

Options

A. `0.0825`
B. `0.825`
C. `0.498`
D. `0.0013`

Answer

A

Explanation

Molality (m) `= ("mass of solvent (in g)" xx 1000)/("molecular weight of solute" xx "mass of solvent (in g)")`
`= (200 xx 10^(-3) xx 1000)/(60 xx 40) = 0.0833`