When concentrated HCl is added to an a queous solution of $C o C l_{2}$ , its colour changes from reddish pink to deep blue. Which complex ion gives colour in this reaction?

[C o C l_{6}]^{4 -}

No worries! We‘ve got your back. Try BYJU‘S free classes today!

[C o C l_{6}]^{3 -}

Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses

[C o (H_{2} O)_{6}]^{2 +}

No worries! We‘ve got your back. Try BYJU‘S free classes today!

[C o C l_{4}]^{2 -}

No worries! We‘ve got your back. Try BYJU‘S free classes today!

Open in App

Solution

The correct option is B $[C o C l_{6}]^{3 -}$
When concentrated $H C l$ is added to an aqueous solution of $C o C l_{2}$ , its colour changes from reddish pink to deep blue. $C o (I I)$ is oxidized to $C o (I I I)$ .
This indicates the formation of $[C o C l_{6}]^{3 -}$ .
$C o C l_{2} H C l - - \to [C o C l_{6}]^{3 -}$ .

Suggest Corrections

Similar questions

An aqueous pink solution of cobalt(II) chloride to deep blue on addition of excess of HCL. This is because ..........
(a) $[C o (H_{2} O)_{6}]^{2 +}$ is transformed into $[C o C l_{6}]^{4 -}$
(b) $[C o (H_{2} O)_{6}]^{2 +}$ is transformed into $[C o C l_{4}]^{2 -}$
(c) tetrahedral complexes have smaller crystal field splitting than octahedral complexes
(d) tetrahedral complexes have larger crystal field splitting than octahedral complex.

Q. When concentrated HCl is added to a solution of

[C o (H_{2} O)_{6}]^{2 +}

ion, an intense blue colour develops due to the formation which one of the following?

Q. The aqueous solution of transition metal salt changes colour from pink to blue, when concentrated hydrochloric acid is added to it. The change in colour is due to

Q. When hydrochloric acid is added to cobalt nitrate solution at room temperature, the following reaction takes place and the reaction mixture becomes blue. On cooling the mixture it becomes pink. On the basis of this information mark the correct answer.

[C o (H_{2} O)_{6}]^{3^{+}} (a q)      p i n k + 4 C l^{-} (a q) ⇋ [C_{o} C l_{4}]^{2^{-}} (a q)      b l u e + 6 H_{2} O (l)

[C o C l_{4}]^{2 -}

(blue) and

[C o (H_{2} O)_{6}]^{2 +}

(pink) have different colours because of

Δ_{t e t} < Δ_{o c t}

.
If true enter 1, else enter 0.

Join BYJU'S Learning Program

When concentrated HCl is added to an a queous solution of CoCl2, its colour changes from reddish pink to deep blue. Which complex ion gives colour in this reaction?

The correct option is B [CoCl6]3−When concentrated HCl is added to an aqueous solution of CoCl2, its colour changes from reddish pink to deep blue. Co(II) is oxidized to Co(III).This indicates the formation of [CoCl6]3−.CoCl2HCl−−→[CoCl6]3−.

When concentrated HCl is added to an a queous solution of $C o C l_{2}$ , its colour changes from reddish pink to deep blue. Which complex ion gives colour in this reaction?