Question

5. What is the mole fraction of NaOH in an aqueous solution that contains 31.0 % NaOH by mass?

Answer 1

Answer:

16.8%      

Explanation:

31% NaOH    molar mass  40 gm

69% H2O      molar mass  18  gm

1000 gm would be  

 310 gm NaOH  or  310/40 = 7.75 moles

 690 gm of H2O or  690/18 = 38.333 moles

7.75 / (7.75 + 38.333) = .168   mole fraction