Question

Re-write the chemical reaction for the CoCl₄^2- complex. You may refer to the experimental procedure.

CoCl₄^2- (aq) + 6H₂O (l) Û 4Cl^- + Co(H₂O)₆²⁺ (aq) + energy

(purple/blue)                            (pink)

A completed data table #3.

Change to the Reaction	Drops added	Visual observation	Shift in the reaction (to the products, to reactants, or no change)
Test tube 1: CoCl2 + water	4	To begin, the solution was a purple/blue color. There were no solids in the solution. Although, after the reaction the solution turned to a pale pink color. No precipitate was formed, and no exothermic or endothermic reaction was observed.
Test tube 1: Cocl2 +water+ concentrated HCl	4	The solution went from a pink color to a purple, almost blue color. The purple/blue color first only appeared near the bottom of the test tube, but once mixed the entire solution was a blue color. An exothermic reaction was observed, as the test tube became warmer after the reaction.
Test tube 2: CoCl2 + water + heat		Once the solution was added to heat, the solution instantly turned a purple color. No precipitate was observed after or during heating of the solution.
		When the test tube was entered into the ice bath, the color immediately went back to a pink color.
Test tube 3: CoCl2 + AgNO3	2	After the solutions were mixed, a cloudy white solution was formed. There were small white precipitates that could be seen floating throughout the solution, as well at the bottom of the test tube. There was no exothermic or endothermic reaction observed.
Test tube 4: CoCl2 + KNO3	4	A clearer, more transparent pink solution was observed. After the reaction occurred, the test tube became slightly warmer indicating an exothermic reaction. No precipitates or solids were observed in the test tube.

Using equation 5, interpret your observations in terms of Le Châtelier’s principle when you placed the test tube containing the pink solution in a hot water bath.

Need the shift in reaction thats needed in the table, and the new equation thats stated under the table.

Answer 1

Test tube - 1	The formation of complex is slow and reaction is shifting towards right
Test tube - 1	In presence of HCl reaction is shifting towards left to produce more initial complex. means pink coloured complex is not stable in acidic medeum
Test tube - 2	on heating the reaction is shifting on left hand side means the forward reaction is an exhothermic in nature. so for the formation of pink complex lower temperature is favoured
Test Tube - 3	The observation indicates that the blue coloured solution contains free chlorides which react with silvernitrate to give ppt. means no shifting toward right side.
Test tube - 4	reaction with KNO3 is exothermic and it shits the reaction toward right hand side to produce more pinc complex.