Question

Dissolving `120g` of urea `(Mw = 60)` in `1000 g` of water gave a solution of density `1.15 g mL^(-1)`. The molarity of solution is:
A. `1.78 M`
B. `2.00 M`
C. `2.05 M`
D. `2.22 M`

Answer 1

Correct Answer - C
Total mass of solution `= 1000+120=1120 g`
Total volume of solution `= (1120)/(1.15) = 973.9 mL`
molarity `= (w xx 1000)/(m xx V_("in mL")) = (120 xx 1000)/(60 xx 973.6) = 2.05 M`