Question 3. 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 substance dissolved in 100 grams of water to form a saturated solution).
(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) At 313K 62g of potassium nitrate dissolved in 100g of water. So to produce a saturated solution of potassium nitrate in 50g of water we need
of potassium nitrate.
(b)Some soluble potassium chloride will separate out in the form of crystal at room temperature because the solubility of potassium chloride will decrease.
(i) Solubility of Potassium nitrate at 293K is 32g.
(ii) Solubility of sodium chloride at 293K is 36g.
(iii) Solubility of Potassium chloride at 293K is 35g.
(iv) Solubility of Ammonium chloride at 293K is 37g.
The solubility of Ammonium chloride is highest at this temperature.
(d)The solubility of salt increases with the increase in temperature.