NEET2013ChemistryCoordination CompoundsActual
Assertion : Aq. solution of CoCl ₂ is pink in colour. It turns blue in presence of conc. HCl . Reason : It is due to the formation of [ CoCl ₄ ]²⁻ .
Options
- AIf both assertion and reason are true and reason is the correct explanation of assertion.
- BIf both assertion and reason are true but reason is not the correct explanation of assertion.
- CIf assertion is true but reason is false.
- DIf both assertion and reason are false.
Correct answer
A. If both assertion and reason are true and reason is the correct explanation of assertion.
Step-by-step solution
[ Co ( H ₂ O )₆ ]²⁺+4 Cl ⁻ [ CoCl ₄ ]²⁻+6 H ₂ O Pink Blue According to Le Chatelier's principle, on adding conc. 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.