When hydrochloric acid is added to cobalt nitrate solution at room
temperature, the following reaction takes place and the reaction mixture
becomes blue. On cooling the mixture it becomes pink. Based on this
information mark the correct answer.
[Co (H2O)6]3+ (aq) + 4Cl–(aq) ⇌ [CoCl4]2– (aq) + 6H2O (l)
(i) ∆H > 0 for the reaction
(ii) ∆H < 0 for the reaction
(iii) ∆H = 0 for the reaction
(iv) The sign of ∆H cannot be predicted based on this information.
Option (i) is the answer.