Question

Molarity of aqueous NaOH solution will be, if mole fraction of NaOH in the solution is 0.5
(Density of pure NaOH is 4 gm/ml)

Answer 1

molarity of NaOH solution is = (W/(M*V))
hare mole fraction of NaOH is 0.5
that is 0.5mol H2O+0.5 mol NaOH
i.e. 18*0.5g water+40*0.5g NaOH [MW of water = 18, NaOH=40]
i.e. 9.0g water+20g NaOH
i.e. 9mL water+20/4mL NaOH [Applying v=m/d]
i.e. 9mL water+5mL NaOH
i.e. TOTAL VOL OF THE SOLUTION IS 14mL=14/1000 L
using 1st equation here
now molarity of NaOH solution is = ((20*1000)/(40*14) = 35.71