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. Which complex ion gives blue colour in this reaction?

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

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

{[C o {C l}_{6}]}^{3 -}

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

{[C o {C l}_{4}]}^{2 -}

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

{[C o {C l}_{6}]}^{4 -}

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

Open in App

Solution

The correct option is B ${[C o {C l}_{4}]}^{2 -}$
The correct answer is option $C$ .
Solution:
$[C o (H_{2} O)_{6}]^{2 +} + 4 C l^{-} + h e a t ⇋ C o C l_{4}^{2 -} + 6 H_{2} O$
Here heat is a reactant in this equilibrium. This means that when heat is added i.e., the solution is being heated, the equilibrium will shift in the direction of the products. This shift in the equilibrium will then the solution blue, the colour of the $(C o C l_{4})^{2 -}$ .
Hence, option $C$ is correct.

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. 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 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?

Presence of

{F e}^{3 +}

in an aqueous solution can be made by addition of sodium acetate (in excess) when a reddish-brown colour is formed.

A blue colour solution is formed when potassium ferrocyanide in excess is added to aqueous ferric chloride solution. This blue colour is of__________.

Q. An aqueous pink solution of cobalt(II)chloride changes to deep blue on addition of excess of HCl. This is because

Join BYJU'S Learning Program

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

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. Which complex ion gives blue colour in this reaction?