question_answer

  Rama tested the solubility of four substances at different temperatures and found gram of each substance dissolved in 100 g of water to form a saturated solution.

S. No.	Substance dissolved (in gram)
1.	Ammonium chloride	37 g	41 g	55 g
2.	Potassium chloride	35 g	40 g	46 g
3.	Sodium chloride	36 g	36 g	37 g
4.	Potassium nitrate	32 g	62 g

(i) Which solution is least soluble at 293K?   (ii) Which    substance    shows maximum   change   in   its solubility when the temperature is raised from 293K to 313K? (iii) Find the amount of ammonium chloride that will separate out when 55 g of its solution at 333K is cooled to 293K. (iv) What   is   the   effect   of temperature on the solubility of a salt? (v) What mass of sodium chloride would be needed to make a saturated solution in 10 g of water at 293K?

Answer:

                  (i) Potassium nitrate                                       (1) (ii) Potassium nitrate                                      (1) (iii) At 333K, ammonium chloride dissolved per 100g =55g At 293K, ammonium chloride dissolved perl00g=37g When solution is cooled from 333K to 293K, amount of ammonium chloride that will separate out =55g-37g=18g.                          (1) (iv) Solubility of a salt (soild) increases with rise in temperature and vice-versa.              (1) (v) At 293K, amount of NaCI dissloved in 100g water = 36 g  At 293K amount of NaCI dissolved in 10g water               (1)