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
jamb 1982chemistry

The correct answer is E. 2.0 mole per dm3

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)

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