Qualitative analysis of cobalt II salts
Qualitative analysis of cobalt II salts
Common salt: Cobalt sulphate: CoSO4
(a)With dilute sodium hydroxide solution of ammonium solution
Observation
Blue precipitate insoluble in excess turns brown on standing
Confirmatory test
(a) Forms deep blue solution with concentrated hydrochloric acid.
Co(H2O)62+ (aq) + 4Cl– (aq) → CoCl42- (aq) + 6H2O (l)
(b) With Concentrated ammonia forms a blue precipitate soluble in excess to give pale yellow solution; the solution turns brown on standing.
[Co(H2O)6]2+ (aq) + 2OH– (aq) → Co(OH)2 (s)
pink blue ppt
Co(OH)2 (s) + 6NH3 (aq) s → [Co(NH3)6]2+(aq)
red-brown
[Co(NH3)6]2+(aq) →Co(NH3)6]3+(aq) +e
red-brown yellow solution
Please Subscribe to promote this website. Subscription is free
Share with a friend
Thank you so much