9.8g of solid potassium chlorate (KCIO3) were added to 40 cm3 of water and heated to dissolve all the solid. As he solution cooled, crystals of potassium chlorate started forming at 60°C. The solubility of potassium chlorate at 66°C is therefore?
A. 24.5 mole per dm3 B. 0.2 mole per dm3 C. 10.0 mole per dm3 D. 20.0 mole per dm3 E. 2.0 mole per dm3
Correct Answer: E
Explanation
9.8 gms KCIO3 dissolves in 40 cm3 of H. In 100 cc we have (9.8)/(40) x (100)/(1) = 24.5 gm KCIO3 In 1000 cc we have 10 x 24.5 or 245 gms of KCIO3. But mol wt of KCIO3 is 122.5 Solubility of KCIO3 is (245)/(122.5) = 2 moles per dm3 (E)
