Question

A solution of glucose in water is labelled as 10% w/w, what would be the molality and mole fraction of each component in the solution? If the density of solution is 1.2 g mL⁻¹, then what shall be the molarity of the solution?

Answer 1

10% w/w solution of glucose in water means that 10 g of glucose in present in 100 g of the solution i.e., 10 g of glucose is present in (100 − 10) g = 90 g of water.

Molar mass of glucose (C₆H₁₂O₆) = 6 × 12 + 12 × 1 + 6 × 16 = 180 g mol⁻¹

Then, number of moles of glucose

= 0.056 mol

Molality of solution = 0.62 m

Number of moles of water

= 5 mol

Mole fraction of glucose

And, mole fraction of water

= 1 − 0.011

= 0.989

If the density of the solution is 1.2 g mL⁻¹, then the volume of the 100 g solution can be given as:

Molarity of the solution

= 0.67 M