The molarity of a $70 \%$ (mass/mass) aqueous solution of a monobasic acid ( $X$ ) is $\_\_\_\_$ $

Question

The molarity of a $70 \%$ (mass/mass) aqueous solution of a monobasic acid ( $X$ ) is $\_\_\_\_$ $	imes 10^{-1} \mathrm{M}$ (Nearest integer) [Given : Density of aqueous solution of $(X)$ is $1.25 \mathrm{~g} \mathrm{~mL}^{-1}$ Molar mass of the acid is $70 \mathrm{~g} \mathrm{~mol}^{-1}$ ] .

Professor PC Thomas Classes · Answer

(125) : As the solution is $70 \% ~ w / w$ hence, 100 g solution contains 70 g solute.\ Volume of 100 g solution will be $\frac{100}{1.25} \mathrm{~mL}$\ (Given, density of aqueous solution $(X) =1.25 \mathrm{~g} \mathrm{~mL}^{-1}$ )\ Molarity $=\frac{	ext { Moles of solute }}{	ext { Volume }(\mathrm{mL})} 	imes 1000$\ $=\frac{\frac{70}{70}}{\frac{100}{1.25}} 	imes 1000=12.5$ or $125 	imes 10^{-1} \mathrm{M}$