Hazards
Conc. HCl is corrosive and toxic. Use care.
Chemicals and Solutions
- 1 M CuSO₄ 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
\( \ce{ $\underset{\text{green}}{\ce{CuSO4 + 4Cl- -> [CuCl4]2- }}$ } \)
\( \ce{ $\underset{\text{blue}}{\ce{[CuCl4]2- + 6H2O -> [Cu(H2O)6]2+}}$ } \)