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Question:

The osmotic pressure of an ionic compound XY in water is four times that of a solution of 0.01M BaCl₂ in water. Assuming complete dissociation of the given ionic compounds in water, the concentration of XY (in mol.L⁻¹) in solution is:

6×10⁻²

4×10⁻⁴

16×10⁻⁴

4×10⁻²

Solution:

Correct option is A. 6×10⁻²
Given that
ΠXY = 4 × ΠBaCl₂
Since both are ionic solute, i.e.
XY → X⁺ + Y⁻ ⇒ i = 2
BaCl₂ → Ba²⁺ + 2Cl⁻ ⇒ i = 3
Now using the law,
Π = i × CRT ⇒ 2 × [XY] = 4 × 3 × 0.01 (Assuming the same temperature)
[XY] = 0.06 M