Question

What is the mole fraction of glycerin $C_3{H}_5(OH{)}_3$ in a 100 g solution containing 33 g of glycerin, 60 g isopropyl alcohol and rest water?

• A. 0.359
• B. 0.258
• C. 0.205
• D. 0.480

Answer 1

The correct option is C 0.205

Molar mass of glycerin = 92 g/mol.
Number of moles of glycerin $=33/92=0.3587mol$
Number of moles of isopropyl alcohol = $\frac{60g}{60g/mole}=1mole$
Mass of water =100-(33+60)=7 g
Number of moles of water = $\frac{7g}{18g/mole}=0.3889mole$
Mole fraction of glycerin $=\frac{0.3587}{0.3587+1+0.3889}=0.205$