Question

Write the equilibrium equation for Cobalt II Chloride Solution when conc. hydrochloric acid is added, and state whether the concentration of each of the following substances was increased, decreased or unaffected, when the conc. hydrochloric acid was added to the cobalt II chloride solution?

Answer 1

equilibrium equation for Cobalt II Chloride Solution when conc. hydrochloric acid is added

(Co(H2O)6)2+(aq)(pink) + 4Cl-(aq) ↔ (CoCl4)2-(aq)(blue) + 6H2O.

cobalt(II) chloride solution is of pink color, because of six water molecules attached with it and forms octahedral hexaaquacobalt(II) complex, [Co(H₂O)₆]²⁺:

When the reaction takes place the blue tetrachlorocobaltate(II) complex is formed.

After adding hydrochloric acid, more the concentration of octahedral hexaaquacobalt(II) complex is consumed. And the equilibrium shifts to the right, and more the concentration of blue tetrachlorocobaltate(II) is formed. Contrary, adding more water reverse takes place.