Question

Sugar syrup, usually used to coat sweets with sugar, becomes hard when cooled. From this, we can conclude that sugar syrup is:
A. Saturated solution
B. An unsaturated solution
C. Not a solution
D. None of these

Answer 1

Hint: Saturated solution is a solution where the maximum amount of solute is dissolved in the solvent and unsaturated solution is a solution where a solute is taken less than the maximum possible amount and is dissolved in a solvent. And sugar syrup is a solution of excess sugar and water where sugar is the solute and water is the solvent. Find which solution (saturated or unsaturated) on cooling becomes hard and that will be our answer.

Complete answer:Scientifically sugar is called sucrose which is a combination of glucose and fructose which is found in many plants and fruits.
So naturally sugar is available in the form of crystals. A hot sugar syrup is a mixture of sugar and water which is heated to form a concentrated liquid. We know that converting solid to liquid is called melting.
And to cool this hot sugar syrup, it is then kept in the fridge. On cooling, crystals of sugar get separated from the mixture which is the solid form of sugar. Now this conversion of liquid to solid is called freezing.
Sugar syrup is a saturated solution of sugar in water. Maximum amount of sugar is added in water and undissolved sugar is made dissolved by heating. Syrup becoming hard on cooling indicates that sugar syrup is a saturated solution as excess amount of solute is dissolved in the solvent.

Hence, the correct option is Option A.

Note:Unsaturated solution forms a homogeneous mixture whereas saturated and supersaturated solutions form heterogeneous mixtures as the solute will not be completely dissolved. Heating sugar and water to form sugar syrup and cooling sugar syrup is a physical change to form the crystals again is a physical change as there is no change in color, composition noticed. Be careful while defining saturated and unsaturated solutions as their definitions might confuse us a bit.