Question

5. How difficult do you think it would be to make a 10 M sugar solution? Justify your answer.

Answer 1

It will be impossible to make a 10 M sugar solution at room temperature. Normal sugar consist of sucrose, the maximul solubility of sugar in water at room temperature is about 2000 g/L, at 75 oC the solubility increase to about 3460 g/L and at 90 oC the solubility of sugar is 4200 g/L.

The molar mass of sugar (sucrose) = 342.30 g/mol

Molarity of a saturated sugar solution at room temperature, 2000 g/L = 2000 g/L /342.30 g/mol = 5.8428 M

So at room temperature you can make 5.8 M solution.

At 75 oC, the solubility is 3460 g/L, molarity = 3460 g/L / 342.30 g/mol = 10.1081 M

At 90 oC, the solubility is 4200 g/L, molarity = 4200 g/L / 342.30 g/mol = 12.2699 M

In order to make a 10 M sugar solution you need to heat the solution to 75 oC.

Which makes it practically very difficult as mass of sugar is about 4 times that of water, will be very viscous solution, difficult to handle. Even at room temperature the saturated sugar solution (5.8 M) will be highly viscous as you are dissolving twice quantity of sugar in water.