Question

What are the mole fractions of glucose and water respectively, in 20% (w/w) aqueous glucose solution? (\(C = 12\,u\); \(O = 16\,u\); \(H = 1\,u\))

• A. 0.0244, 0.9756
• B. 0.04, 0.96
• C. 0.0636, 0.9364
• D. 0.0124, 0.9876

Hint:

Calculate mole fractions by converting masses to moles and dividing by total moles.

Answer 1

The Correct Option is A

- Assume 100 g solution: 
Glucose = 20 g, Water = 80 g. 
- Moles of glucose: \[ \frac{20}{180} = 0.111 \] 
- Moles of water: \[ \frac{80}{18} = 4.44 \] - Total moles = \(0.111 + 4.44 = 4.551\) Mole fractions: \[ x_{{glucose}} = \frac{0.111}{4.551} = 0.0244 \] \[ x_{{water}} = \frac{4.44}{4.551} = 0.9756 \]