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← JEE Main 2026 · 5 Apr · Shift 1
ChemistrySingle correct+4 / -1Question 55 of 75

JEE Main 2026 · 5 Apr · Shift 1, Chemistry question 55

MX3AX2\ce{M3A2} is a sparingly soluble salt of molar mass yy g mol−1^{-1} and solubility xx g L−1^{-1}. The ratio of the molar concentration of the anion (AX3−\ce{A^{3-}}) to the solubility product of the salt is

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Answer and worked solution

Official answer: A

Solubility. s=xys=\dfrac xy mol L−1^{-1}. MX3AX2⇌3 MX2++2 AX3−\ce{M3A2 <=> 3M^{2+} + 2A^{3-}}, so [AX3−]=2s[\ce{A^{3-}}]=2s.

Solubility product. Ksp=(3s)3(2s)2=108s5K_{sp}=(3s)^3(2s)^2=108s^5.

Ratio.
2s108s5=154s4=154⋅y4x4.\frac{2s}{108s^5}=\frac1{54s^4}=\frac1{54}\cdot\frac{y^4}{x^4}.

(A)