JEE Main202624 January 2026Evening ShiftChemistryCoordination CompoundsActual
A chromium complex with a formula CrCl ₃ 6 H ₂ O has a spin only magnetic moment value of 3.87 BM and its solution conductivity corresponds to 1: 2 electrolyte. 2.75 g of the complex solution was initially passed through a cation exchanger. The solution obtained after the process was reacted with excess of AgNO ₃ . The amount of AgCl formed in the above process is _ _ _ _ g. (Nearest integer) [Given: Molar mass in g
Correct answer
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Step-by-step solution
The complex CrCl ₃ 6 H ₂ O with magnetic moment 3.87 BM indicates 3.87 = n(n+2) giving n = 3 unpaired electrons, confirming Cr³⁺. A 1:2 electrolyte means structure is [ Cr(H ₂ O )₅ Cl ]²⁺ Cl ₂^- . Molar mass = 52 + 5(18) + 35.5 + 6(18) = 285.5 g/mol. Moles of complex = 2.75/285.5 = 0.00963 mol. After cation exchange, 2 Cl⁻ remain per formula unit (from the 1:2 electrolyte), giving 0.00963 × 2 = 0.01926 mol of free Cl⁻. Reacting with excess AgNO₃: mass of AgCl = 0.01926 × 143.5 = 2.76 g ≈ 3 g (nearest integer).