The mole fraction of ethylene glycol in a 20 % (w/w) aqueous solution (molar masses: glycol 62, water 18) is closest to
A{'text': '0.068', 'label': 'A'}
B{'text': '0.032', 'label': 'B'}
C{'text': '0.100', 'label': 'C'}
D{'text': '0.150', 'label': 'D'}
Answer & Solution
Correct answer: A. {'text': '0.068', 'label': 'A'}
1. Consider 100 g of solution: 20 g glycol + 80 g water.
2. Moles of glycol = 20 / 62 = 0.322 mol.
3. Moles of water = 80 / 18 = 4.444 mol.
4. x_glycol = 0.322 / (0.322 + 4.444) = 0.068.
_Source: NCERT Class 12 Chemistry, Unit 1 "Solutions", Example 1.1_
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