When concentrated HCl is added to aqueous solution of CoCl2, its colour changes from reddish pink to deep blue. Which complex ion gives blue colour in reaction?
Held on 11 Apr 2015 · Verified 6 Jul 2026.
[CoCl6]4−
[CoCl6]3−
[Co(H2O)6]2+
[CoCl4]2−
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