JEE Main · 2026 · 24 Jan 2026 · Shift 1 · Coordination Compounds

Consider a mixture ' X ' which is made by dissolving 0.4 mol of

[Co (NH_{3})_{5} SO_{4}] Br

and 0.4 mol of

[Co (NH_{3})_{5} Br] SO_{4}

in water to make 4 L of solution. When 2 L of mixture ' X ' is allowed to react with excess of

AgNO_{3}

, it forms precipitate ' Y '. The rest 2 L of mixture ' X ' reacts with excess

BaCl_{2}

to form precipitate '

Z

'. Which of the following statements is CORRECT.

Answer: (A)

Solution

Only ions outside the coordination sphere are precipitated.

[Co (N H_{3})_{5} S O_{4}] Br

releases free

B r^{-}

while

[Co (N H_{3})_{5} Br] S O_{4}

releases free

S O_{4}^{2 -}

, and each

2 L

portion holds

0.2 mol

of each complex. With

AgN O_{3}

the free

B r^{-}

gives

0.2 mol

AgBr

Y

, and with

BaC l_{2}

the free

S O_{4}^{2 -}

gives

0.2 mol

BaS O_{4}

Z

. Hence

0.2 mol

Z

is formed.

JEE Main · 2026 · 24 Jan 2026 · Shift 1 · Single correct option