Chemistry - Concentration Terms Question with Solution | TestHub

Molarity $2.5\text{M}$ means $2.5$ moles of urea in $1\text{L}$ of solution. Mass of urea $=2.5\text{mol}\times 60\text{g/mol}=150\text{g}$. Mass of solution $=1000\text{mL}\times 1.05\text{g/mL}=1050\text{g}$. Mass percentage of urea $=\frac{150\text{g}}{1050\text{g}}\times 100=14.28\%$. Therefore, option A is correct.