STANDARDChemistry-Solutions
STANDARD Chemistry Mole Fraction MCQ Question
Type: MCQ-numerical-Medium-Class 12
What will be the mole fraction of ethanol in a sample of spirit containing 85% ethanol by mass?
A
0.69
B
0.82
C
0.85
D
0.60
Correct Answer
Option A
Detailed Explanation
The mole fraction of ethanol is calculated by dividing the moles of ethanol by the total moles of the solution. Given 85 g of ethanol and 15 g of water, the moles of ethanol (C₂H₅OH) is 1.85 mol and the moles of water (H₂O) is 0.833 mol. The mole fraction is 1.85 / (1.85 + 0.833) = 0.69.
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