If 4g of NaOH dissolves in 36 g of H2O, calculate the mole fraction of each component in the solution. Also, determine the molarity of solution (specific gravity of solution is 1 g mL−1).
Number of moles of NaOH.
nNaOH=440=0.1 mol {∵n=Mass(g)Molar mass}
Similarly, nH2O=3618=2 mol
Mole fraction of NaOH,XNaOH=moles of NaOHmoles of NaOH+moles of H2O
XNaOH=0.10.1+2=0.0476
Similarly, XH2O=nH2OnNaOH+nH2O=20.1+2=0.9524
Total mass of solution = mass of solute + mass of solvent
= 4 + 36 = 40 g
Volume of solution =Mass of solutionspecific gravity=40 g1 g mL−1=40 mL
Molarity=Moles of solute×1000Volume of solution(mL)=0.1×100040=2.5M