Question

The solubility of KNO3 is 32g/100g of water at 20oC and 62g/100g of water at 40oC. What will you observe if a saturated solution of KNO3 at 400C is cooled to 20oC.

Answer 1

Step-by-step explanation:

Solubility of KNO₃ at 20° C = 32 g / 100g of water

that means , per 100 g of water maximum of 32 g of KNO₃ can be dissolved at 20° C .

Solubility of KNO₃ at 40° C = 62 g / 100g of water

that means , per 100 g of water maximum of 62 g of KNO₃ can be dissolved

40° C.

So when a saturated solution in which maximum KNO₃ has been dissolved is cooled from 40° C to 20° C , due to decrease in solubility at lower temperature some KNO₃ will come out of the solution . Per 100 gram of saturated solution , 62 - 32 = 30 g of KNO₃ will precipitate out or come out of water . They can be filtered out .