Question

What is the molarity of $H _{2} SO _{4}$ solution that has a density of $1.84\, g / cc$ at $35^{\circ} C$ and contains $98 \%$ by weight?

• A. 4.18 M
• B. 8.14 M
• C. 18.4 M
• D. 18 M

Answer 1

Answer: (C)

18.4 M

Answer 2

Molarity $=\frac{\text { wt. of solute }}{\text { mol. wt. }} \times \frac{1000}{\text { vol. of solution (in ml.) }}$ (Volume of solution $=\frac{\text { mass }}{\text { density }}=\frac{100}{1.84}$ $=54.34\, ml$ ) Now molarity $=\frac{98}{98} \times \frac{1000}{54.34}$ $=18.4 \,M$