Answer :
(a) Given:
Mass of potassium nitrate required to produce a saturated solution in 100 g of water at 313 K = 62g
Mass of potassium nitrate required to produce a saturated solution in 50 g of water
= \( 62 \) × \( 50 \over 100 \) \( = 31 \ g \)
Hence 31 g of potassium nitrate is required to form a saturated solution of it at the given temperature.
(b) Pragya would observe crystals of potassium chloride as the solubility of potassium chloride in water decreases when a saturated solution of potassium chloride loses its heat during the cooling process below 353 K.
(c) Listed below is the solubility of each salt at 293 K:
Solubility of Potassium nitrate —> 32g
Solubility of Sodium chloride —> 36g
Solubility of Potassium chloride —> 35g
Solubility of Ammonium chloride —> 37g
Ammonium chloride has the highest solubility at this temperature.
(d) Solubility of a salt is directly proportional to the change of temperature. Solubility of salt will increase when the temperature increases and solubility will decrease when the temperature decreases .