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JAMB Chemistry 1990 Question 18

Question 18

Mole Concept and Stoichiometry

Na2C2O4 + CaCl2 → CaC2O4 + 2NaCl. Given a solution of 1.9 g of sodium oxalate in 50 g of water at room temperature, calculate the minimum volume of 0.1 M calcium chloride required to produce maximum calcium oxalate using the above equation.

  1. A.1.40 × 102 dm3
  2. B.1.40 × 102 cm3
  3. C.1.40 × 10−2 dm−2
  4. D.1.40 × 10−2 cm3.
Show the answer and explanation

Answer: B (1.40 × 102 cm3)

Explanation

Moles of Na2C2O4 = 1.9 ÷ 134 = 0.0142, and the same number of moles of CaCl2 is needed. Volume = 0.0142 ÷ 0.1 = 0.142 dm3 = 1.40 × 102 cm3.