JEE Main · 2026 · 24 Jan 2026 · Shift 2 · Coordination Compounds

A chromium complex with a formula

CrCl_{3} \cdot 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 mol^{- 1}

Cr: 52; Cl: 35.5, Ag: 108, O: 16, H: 1]

Answer: 3

Solution

A spin-only moment of

3.87 BM

corresponds to three unpaired electrons, i.e.

C r^{3 +}

(

d^{3}

). A

1 : 2

electrolyte furnishes one cation and two anions, so the complex is

[C r (H_{2} O)_{5} C l] C l_{2} \cdot H_{2} O

, of molar mass

52 + 5 (18) + 35.5 + 2 (35.5) + 18 = 266.5 g mol^{- 1}

. Moles taken

= \frac{2.75}{266.5} = 0.01032

. A cation exchanger retains the complex cation and releases only the two ionisable chloride ions, which precipitate with

A g N O_{3}

n_{A g C l} = 2 \times 0.01032 = 0.02064

. Mass of

A g C l

(molar mass

143.5

)

= 0.02064 \times 143.5 = 2.96 g

, i.e.

3 g

to the nearest integer.

JEE Main · 2026 · 24 Jan 2026 · Shift 2 · Integer answer

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JEE Main · 2026 · 24 Jan 2026 · Shift 2 · Coordination Compounds

Solution

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