Pragya tested the solubility of three different substances at different temperatures and collected the data as given below (results are given in the following table, as grams of a substance dissolved in 100 grams of water to form a saturated solution).

Substance Dissolved	Temperature in K
	283	293	313	333	353
	Solubility
Potassium nitrate	21	32	62	106	167
Sodium chloride	36	36	36	37	37
Potassium chloride	35	35	40	46	54
Ammonium chloride	24	37	41	55	66

(a) What mass of potassium nitrate would be needed to produce a saturated solution of potassium nitrate in 50 grams of water at 313 K?

(b) Pragya makes a saturated solution of potassium chloride in water at 353 K and leaves the solution to cool at room temperature. What would she observe as the solution cools? Explain.

(c) Find the solubility of each salt at 293 K. Which salt has the highest solubility at this temperature?

(d) What is the effect of change of temperature on the solubility of a salt?

(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 = ?

Required amount = $\dfrac{62}{100}$ x 50 = 31

Hence, 31 g of potassium nitrate is required.

(b) The solubility of potassium chloride in water is decreased when the saturated solution of potassium chloride loses heat at 353 K. So, Pragya would observe crystals of potassium chloride, which would have surpassed its solubility at low temperatures.

(c) As per the given data :

Solubility of potassium nitrate at 293 K = 32 g

Solubility of sodium chloride at 293 K = 36 g

Solubility of potassium chloride at 293 K = 35 g

Solubility of ammonium chloride at 293 K = 37 g

We can observe from this data that ammonium chloride has the highest solubility at 293 K.

(d) The solubility of the salt increases with an increase in temperature.