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JAMB Chemistry 1981 Question 36

Question 36

Solubility and Solutions

5 cm3 of a saturated solution of sodium chloride at 30°C gave, on careful evaporation, 1.95 g of solid salt. The solubility of sodium chloride at 30°C is (Na = 23, Cl = 35.5)

  1. A.5.00 mole dm−3
  2. B.5.67 mole dm−3
  3. C.6.00 mole dm−3
  4. D.6.67 mole dm−3
  5. E.7.00 mole dm−3.
Show the answer and explanation

Answer: D (6.67 mole dm−3)

Explanation

1.95 g in 5 cm3 is 390 g per dm3. Dividing by the molar mass 58.5 g gives 6.67 mol dm−3.