molality of 2%w/w NacCl solution is?

2 % w/w means 2 g of NaCl (solute) in 100 g of NaCl solution.
Number of moles of NaCl (n) = $\frac{\text{Given mass}}{\text{Molar mass}}$
n = $\frac{2}{58.5}$ = 0.0341 moles
Mass of solvent = Mass of solution - mass of solute
Mass of solvent = 100 - 2 = 98 g (0.098 kg)
Molality = $\frac{\text{Number of moles of solute}}{\text{Mass of solvent in kg}}$
Molality = $\frac{0.0341}{0.098}$ = 0.347 m