Question

56. If 0.04 M solution of Na2SO4 (100% ionization) is
isotonic with aqueous solution of glucose at 27°C,
then molarity of aqueous solution of glucose is
(1) 0.2 M
(2) 0.3 M
(3) 0.12 M
(4) 0.5 M​

Answer 1

Molarity of the given aqueous solution of glucose is 0.12 M.

• 100 % ionization of Na₂SO₄ gives 2 Na⁺ and 1 SO₄⁻ ion.
• Hence, 1 mole of Na₂SO₄ gives 3 moles of ions.
• Therefore, the molarity of the aqueous solution with 100% ionization is 0.04 * 3 = 0.12 M
• Since an isotonic solution means that the two solutions are having same molarity, the molarity of the aqueous solution of glucose is 0.12 M.