• # question_answer 76)   The density of 3 molal solution of $NaOH$ is $1.110\,g\,m{{L}^{-1}}$.Calculate the molarity of the solution.

3 mol $NaOH$ is dissolved in 1000 g solvent. Thus, Mass of solution $=1000+40\times 3=1120g$ Volume of solution $=\frac{Mass}{Density}=\frac{1120}{1.11}=1009mL.$ Molarity of solution can be calculated as: $M=\frac{{{w}_{B}}\times 1000}{{{m}_{B}}\times V}=\frac{120\times 1000}{40\times 1009}=2.97$