Question

100 mL of water at room temperature of 25°C is taken in a beaker and a little of solid S is dissolved in it by stirring to obtain a solution X. More and more of solid S is added to the solution with constant stirring, while keeping the temperature of solution constant at 30°C. After some time it is observed that no more solid dissolves in water and at the same time some solid is also left undissolved at the bottom of the beaker.

1. The contents of beaker are filtered through a filter paper to obtain solution Y in the form of a filtrate.
2. What name is given to solutions like X ?
3. What name is given to solutions like Y ?
4. What will you observe if the solution Y at 30°C is cooled down to 10°C by keeping the beaker in crushed ice ? Why ?
5. What term is used to denote the amount of solid dissolved in 100 grams of water in a solution lie Y ?

Answer 1

1. X type of solutions is known as unsaturated solution.
2. Y type of solutions is known as saturated solution.
3. If solution Y at 30°C is cooled down to 10°C by keeping the beaker in crushed ice, some of the dissolved parts of the solid will separate from the solution and will settle at the bottom of the beaker as crystals. This occurs because of the decrease in the solubility of solids and reduction in temperature.
4. Solubility refers to the amount of a solid dissolved in 100 grams of water.