Question

What is the mole fraction of solute in a 5 m aqueous solution?

• A. 0.038
• B. 0.593
• C. 0.082
• D. 0.751

Hint:

To calculate the mole fraction of solute, remember that the moles of water are calculated by dividing the mass of water (in grams) by the molar mass of water (18 g/mol).

Answer 1

The Correct Option is C

We are given a 5 m aqueous solution, meaning there are 5 moles of solute dissolved in 1 kg of solvent (water). To calculate the mole fraction of solute, we use the following formula: \[ \text{Mole fraction of solute} = \frac{\text{Moles of solute}}{\text{Moles of solute} + \text{Moles of solvent}} \] For 1 kg of water, the number of moles of solvent (water) is: \[ \text{Moles of water} = \frac{\text{Mass of water}}{\text{Molar mass of water}} = \frac{1000 \, \text{g}}{18 \, \text{g/mol}} = 55.56 \, \text{mol} \] Now, the mole fraction of solute is: \[ \text{Mole fraction of solute} = \frac{5 \, \text{mol}}{5 \, \text{mol} + 55.56 \, \text{mol}} = \frac{5}{60.56} = 0.082 \] Thus, the mole fraction of the solute is 0.082.