Q. A solution is prepared by dissolving 24.5 g of sodium hydroxide in distilled water to give 1L solution. The molarity of NaOH in the solution is (Given, that molar mass of NaOH $= \ 40.0\ g\ {mol}^{- 1}$)
A) 0.2450 M
B) 0.6125 M
C) 0.9800 M
D) 1.6326 M
Explanation
(b)
Given, w = 24.5 g
V = 1L = 100 mL
M =?
Mol. wt. of NaOH = 23+16+1=40
We know that,
M= $\frac{w \times 1000}{m\ \times \ V}$ =$\frac{24.5\ \times \ 1000}{40\ \times \ 1000}$
$\therefore$ Molarity of solution = 0.6125 M
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.