The molarity of solution containing `15.20 g` of urea, (molar mass = 60) dissolved in `150 g` of water is

Options

A. `1.689` `mol kg^(-1)`
B. `1689` `mol kg^(-1)`
C. ` 0.5922` `mol kg^(-1)`
D. `0.2533` `mol kg^(-1)`

Answer

A

Explanation

Molarity
(m) `= ("Number of moles of solute")/("Mass of solvant (in g)") xx 1000`
`= ("Mass of solute (in g)")/("Molecular weight of solute") xx "mass of solvent (in g)"`
`= (W_("solute") xx 1000)/(M_("solute") xx W_("solvant"))`
`= (15.2 xx 1000)/(60 xx 50) = 1689 "mol" kg^(-1)`