Assertion: Aq. solution of CoCl2 is pink in colour. It turns blue in presence of conc. HCl. Reason: It is due to the formation of [CoCl4]2-.

Question

Assertion: Aq. solution of CoCl2 is pink in colour. It turns blue in presence of conc. HCl. Reason: It is due to the formation of [CoCl4]2-. (A) If both assertion and reason are true and reason is the correct explanation of assertion. (B) If both assertion and reason are true but reason is not the correct explanation of assertion. (C) If assertion is true but reason is false. (D) If both assertion and reason are false.

Tardigrade Admin · Accepted Answer

[ Co ( H 2 O )6]2++4 Cl - leftharpoons[ CoCl 4] text Blue 2-+6 H 2 O According to Le Chatelier's principle, on adding cone. HCl, the equilibrium shifts in forward direction giving blue colour. And when this blue colour is diluted, equilibrium shifts in backward direction leading to pink colour.

Q. Assertion : Aq. solution of CoCl2​ is pink in colour. It turns blue in presence of conc. HCl. Reason : It is due to the formation of [CoCl4​]2−.

If both assertion and reason are true and reason is the correct explanation of assertion.

If both assertion and reason are true but reason is not the correct explanation of assertion.

If assertion is true but reason is false.

If both assertion and reason are false.

[Co(H2​O)6​]2++4Cl−⇌[CoCl4​]Blue 2−​+6H2​O According to Le Chatelier's principle, on adding cone. HCl, the equilibrium shifts in forward direction giving blue colour. And when this blue colour is diluted, equilibrium shifts in backward direction leading to pink colour.

Q. Assertion : Aq. solution of $C o C l_{2}$ is pink in colour. It turns blue in presence of conc. $H Cl$ .
Reason : It is due to the formation of $[C o C l_{4}]^{2 -}$ .