Question

part 1 what is the molality of a solution that is 4.23% by mass sodium iodide

part 2 what is the molarity of the above solution (from part#1) if the density of the solution was calculated to be 1.03 g/ml?

Answer 1

4.23% w/w means 4.23 g NaI/(4.23 g NaI + 95.77 g H2O)

Then m = mols NaI/kg H2O.

part 2.
Again, 4.23% NaI means 4.23 g NaI/100 g solution. Density of the solution is 1.03 g/mL. volume of the 100 g solution = mass/density. Then M = mols NaI/L solution.
Post your work if you get stuck.