The oxidation state of Cr in $\left[\mathrm{Cr}\left(\mathrm{NH}_{3}\right)_{4} \mathrm{Cl}_{2}\right]^{+}$ is

JEE Main · 2005 · 08 May 2005 · Offline · Coordination Compounds

The oxidation state of Cr in

[Cr (NH_{3})_{4} Cl_{2}]^{+}

(A)+3✓ Correct
(B)+2
(C)+1
(D)0

Answer: (A)

Solution

The oxidation state of the metal is found by making the charges across the whole complex add up. Ammonia is a neutral ligand and contributes nothing, each of the two chlorides carries

- 1

for a total of

- 2

, and the complex ion as a whole carries

+ 1

. Writing chromium's oxidation state as

x

, the balance

x + (- 2) = + 1

gives

x = + 3

JEE Main · 2005 · 08 May 2005 · Offline · Single correct option

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