Interaction | Reaction | Process     Data Page

When a little dilute ammonia solution is added to a solution of pink hexaaquacobalt(II) ion, the complex cation acts as a Brønsted acid and loses two protons giving a precipitate of blue tetraaquadihydroxycobalt(II) and ammonium ions.

On standing in air the blue ppt. turns pink and then brown.

[Co(H2O)6]2+
  +  
2
NH3(aq)
         

Co(H2O)4(OH)2
Co(OH)2
  +  
2
[NH4]+
Reactant Page Go To Go To
Hexaaquacobolt(II) ion     Reactions Using    Reactions Forming
Ammonia, aqueous     Reactions Using    Reactions Forming
Tetraaquadihydroxycobalt(II)     Reactions Using    Reactions Forming
Ammonium ion     Reactions Using    Reactions Forming

Interaction, Reaction, Process defined as:
British A-Level Chemistry: A2
Precipitation
Proton transfer: Brønsted reaction

© Mark R. Leach 1999 –

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