Question

one of the test tubes will be put in the cold water bath(ice,on scoop of salt and water in a 250ml beaker)for five minutes.one of the test tubes will be put in a 60 degrees celcius warm water bath for 5 minutes.Put all three test tubes in 125 ml erlenmeyer flasks to stand them up,and compare the colors,below is the equillibrium equation that governs the reaction. Bases on this,determine if the reaction is exothermic or endothermic. [Co(H2O)6]2+ +4HCL------[CoCL4]2- + 6h20

Answer 1

Solution :

The given  equilibrium is as follows :

[Co(H2O)6]2+ + 4 HCl  <=> [CoCl4]2- + 6 H2O

The complex Co(H2O)62+ is pink in color. Heating of solution shifted the equilibrium towards forward direction and color of solution changes from pink to blue. Thus reaction is an example of endothermic reaction so adding heat causes the equilibrium constant to shift to the right. This makes the solution blue.

Therefore, reaction is endothermic.