Atomic structure - transition metals- coloured complexes experiment (part 2)

Transition metal complexes part 3
Complexes of iron Place 3ml of 0.1M iron(II)sulfate solution into a small test tubes.
	Add a few drops of potassium thiocyanate. Fe(SCN)⁺² ions are formed. Click to see a 120kb movie The solution turns blood red. What causes this colour change? Has this anything to do with why mammalian blood is coloured red? Explain.
Place 0.1 M iron(II)sulfate solution in a test tube to a depth of 3 cm. Add three drops of hydrogen peroxide solution. Click to hide The Fe(H₂O)₆²⁺ ions that were initially present in the solution become Fe(H₂O)₆³⁺. Why is hydrogen peroxide added? Click to see the electrochemical series. Click to see a 120 kb video.
To the test tube with the Fe(H₂O)₆³⁺solution slowly add ten drops of concentrated hydrochloric acid (HCl). the solution become FeCl₄^1- are formed. The solution turns yellow as shown on the right. Click to see a 120 kb video.
Preparation of an iron complex.