Question

When hydrochloric acid is added to cobalt nitrate solution
at room temperature, the following reaction takes place and
thus the reaction mixture becomes blue. On cooling the
mixture it becomes pink. On the basis of this information
mark the correct answer.
[Co(H₂O)₆]³⁺ (aq) + 4Cl⁻ (aq) ⇋
(Pink)
[CoCl₄]²⁻ (aq) + 6H₂O(1)
(Blue)
(a) ∆H > 0 for the reaction
(b ) ∆H < 0 for the reaction
(c ) ∆H = 0 for the reaction
(d) The sign of ∆H cannot be predicted on the basis of
this information

Answer 1

Answer:

(a) ∆H > 0 for the reaction

Explanation:

Since the reaction shifts to backward direction on cooling, this means that the backward reaction is exothermic reaction. Therefore, the forward reaction is endothermic reaction and hence ∆H > 0 for the reaction

Answer 2

Answer:

on cooling, this means that the backward reaction is exothermic reaction. Therefore, the forward reaction is endothermic reaction and hence ΔH>0.