Question

When hydrochloric aicd is addded to cobalt and nitrate solution at room temperautre, the following reaction takes place and the reaction mixture becomes blue. On cooling the mixture it becomes pink. On the basis of this information mark the corect ansewer.
`underset("pink")[[Co(H_(2)O)_(6)]]^(3+)(aq)+4CI^(-)hArr`
`underset("blue")[CoCI_(4)]^(2-)(aq)+6H_(2)O(l)`
A. `DeltaHgt0` for the reaction
B. `Delta Hlt0` for the reaction
C. `Delta H=0` for the reaction
D. The sign of `DeltaH` cannot be predicted on the basis of this information

Answer 1

Correct Answer - A
Since upon cooling, the equilirium has shifted in the backward dirction. This means that backward reaction is exothermic naure and `DeltaHgt0` for the reaction.