The density of 4% (w/v) NaOH solution is 1.02 g/ml. What is the molality of the solution ?

Explanation

4% of (w/v) NaOH solution contains 4g of NaOH is 100ml of the solution
density of the solution =1.02g/ml.
wt of the solute in 100ml of the solution =4g
wt of 100 ml of the solution `=100 xx 1.02 =102g`
wt. of the solvent =Wt of solution -Wt of the solute
Molality `=((W)/(G.M.W))_("solute") xx (1000)/("wt of solvent in grams")`
`=(4)/(40) xx (1000)/(98)=1.02m`