Q. The molarity of 20.0 mass % $H_{2}SO_{4}$ solution of density 11.14 g $cm^{- 3}$ is
A) 2.56 mol $dm^{- 3}$
B) 1.56 mol $dm^{- 3}$
C) 1.26 mol $dm^{- 3}$
D) 2.32 mol $dm^{- 3}$
Explanation
(d)
Volume of 100 g solution, $V = \frac{m}{\rho}$
$= \frac{100g}{1.14g\ cm^{- 3}} = 87.72cm^{3}$
Amount of sulphuric acid in 100 g solution,
$n = \frac{m}{M} = \frac{20.0g}{98\ g\ mol^{- 1}} = 0.207\ mol$
Molarity of sulphuric acid,
$M = \frac{n}{V} = \frac{0.207\ mol}{87.72 \times 10^{- 3}dm^{3}} = 2.32\ mol\ dm^{- 3}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.