# Copper Equilibrium

## Hazards

Conc. HCl is corrosive and toxic. Use care.

## Chemicals and Solutions

• 1 M CuSO solution
• Concentrated HCl

## Materials

• 2 test tubes
• Eyedropper
• Distilled water

## Procedure

• Add some copper solution to one test tube.
• Add some water to the solution - nothing happens except the solution gets more dilute.
• Add some copper solution to the other test tube and add some concentrated HCl to the solution - it will turn green.
• Add some water to the now green solution and it will turn blue again.

## Discussion

$$\ce{ \underset{\text{green}}{\ce{CuSO4 + 4Cl- -> [CuCl4]2- }} }$$

$$\ce{ \underset{\text{blue}}{\ce{[CuCl4]2- + 6H2O -> [Cu(H2O)6]2+}} }$$