Question

what mass of solution of 0.50 molal glucose solution is required to obtain 0.15 mol glucose ? options - a.327 g .b. 300 g . c.273 g .d. none of these

Answer 1

Answer : The correct option is, (a) 327 g

Solution : Given,

Molality of solution = 0.50 molal = 0.50 mole/Kg

Molar mass of glucose = 180 g/mole

Moles of solute (glucose) = 0.15 moles

First we have to calculate the mass of solvent from the molality.

Formula used :

$Molality=\frac{\text{Moles of solute}}{\text{Mass of solvent}}$

$0.50mole/Kg=\frac{0.15moles}{\text{Mass of solvent}}$

$\text{Mass of solvent}=0.3Kg=0.3\times 1000g=300g$

The mass of solvent = 300 g

Now we have to calculate the mass of solute.

$\text{Mass of solute}=\text{Moles of solute}\times \text{Molar mass of solute}=0.15moles\times 180g/mole=27g$

The mass of solute = 27 g

Now we have to calculate the mass of solution.

Mass of solution = Mass of solute + Mass of solvent

Mass of solution = 27 g + 300 g = 327 g

Therefore, the mass of solution is, 327 g