32 g methanol is mixed with 84 g water. Molar masses are 32 and 18 g mol−1, respectively. What is the approximate mole fraction of methanol?
Answer and explanation
Correct answer: 0.176
Mole fraction depends on the number of moles, not directly on masses. Methanol moles = 32 ÷ 32 = 1 mol, and water moles = 84 ÷ 18 ≈ 4.67 mol. Total moles are about 5.67, so the methanol mole fraction is 1 ÷ 5.67 ≈ 0.176. Thus option A is correct. Option B is approximately the water mole fraction; the other values do not follow the mole-fraction calculation.
Frequently asked questions
What is the correct answer to this question?
0.176
Why is this the correct answer?
Mole fraction depends on the number of moles, not directly on masses. Methanol moles = 32 ÷ 32 = 1 mol, and water moles = 84 ÷ 18 ≈ 4.67 mol. Total moles are about 5.67, so the methanol mole fraction is 1 ÷ 5.67 ≈ 0.176. Thus option A is correct. Option B is approximately the water mole fraction; the other values do not follow the mole-fraction calculation.
Which subject and chapter does this question cover?
This is a Class 11 Chemistry question. Chapter: Chapter 01: Solutions.
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