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JAMB Chemistry 1986 Question 10

Question 10

Solubility and Solutions

When 50 cm3 of a saturated solution of sugar (molar mass 342.0 g) at 40°C was evaporated to dryness, 34.2 g of dry solid was obtained. The solubility of sugar at 40°C is

  1. A.10.0 moles dm−3
  2. B.7.0 moles dm−3
  3. C.3.5 moles dm−3
  4. D.2.0 moles dm−3
Show the answer and explanation

Answer: D (2.0 moles dm−3)

Explanation

34.2 g is 0.1 mol of sugar in 50 cm3. In 1000 cm3 that is 0.1 × 20 = 2.0 mol, so the solubility is 2.0 mol dm−3.