If 4 g of NaOH dissolves in 36g of ${{H}_{2}}$O, calculate the mole fraction of each component in die solution. Also, determine the molarity of solution (specific gravity of solution is lg m${{l}^{-1}}$)

If 4 g of NaOH dissolves in 36g of ${{H}_{2}}$O, calculate the mole fraction of each component in die solution. Also, determine the molarity of solution (specific gravity of solution is lg m${{l}^{-1}}$)