Question

Calculate Molarity of 40% NaOH (w/W). The density of solution is 1.2 g/ml.

Answer 1

40 % NaOH (w/W) means that 40 g pure NaOH is present in 100 g f solution.
Volume of solution `=("Mass of solution")/("density")=(100)/(1.2)ml`
Molarity (M) `=(w/m)/("V (in ml)/1000")=(w)/(m)xx(1000)/("V(in ml)")`
`=(40)/(40)xx(1000)/(100)xx1.2=12 M`
Molality (m) `=("w/m")/("Mass of solvent (in kg)")=(40//40)/(((100-40))/(1000))`
`=(40)/(40)xx(1000)/(60)=16.66 m`