A solution contains 20% of ethylene glycol (C2H6O2, molar mass 62 g/mol) by mass in water. Taking 100 g of solution, the mole fraction of ethylene glycol is:
A0.322
B0.068
C0.200
D0.932
Answer & Solution
Correct answer: B. 0.068
1. In 100 g solution: 20 g glycol and 80 g water.
2. Moles of glycol = $20 / 62 = 0.322$ mol; moles of water = $80 / 18 = 4.444$ mol.
3. $x_{glycol} = 0.322 / (0.322 + 4.444) = 0.322 / 4.766$.
4. $x_{glycol} = 0.068$.
_Source: NCERT Class 12 Chemistry Ch 1 "Solutions", p.3_
Related questions
The mass of NaOH (M = 40 g/mol) required to prepare 500 mL of a 0.20 M NaOH solution isWhich of these solutions will boil at the highest temperature at 1 atm?The molality of a 1 M aqueous NaCl solution (density = 1.04 g/mL, NaCl M = 58.5 g/mol) is Osmotic pressure π of a dilute solution obeys π = C R T. Here C representsVan't Hoff factor i > 1 for a solute indicatesA negative deviation from Raoult law is expected whenIf a solute dimerises in solution, its observed molar mass compared with the calculated vaWhich of the following is NOT a colligative property?