Vanadium Oxidation States

• Vanadium is a transition metal which has variable oxidation states
• Vanadate(V) ions can be reduced to oxidised vanadium species with the oxidation states II, III and IV by using zinc in acidic conditions
• You could be asked to carry out a test tube practical to observe the different colour changes and calculate the oxidation state of the vanadium species produced

Practical

1. Add a quarter of a spatula of ammonium vanadate(V) to a test tube
2. Using a dropping pipette, half-fill the test tube with 1.0 mol dm?3?hydrochloric acid and shake gently
3. Note your observations
4. Add one small piece of zinc, and gently shake the test tube
5. Note your observations over a period of 15 minutes

Vanadium results table

Answer:

The solid dissolves in the acid to form a yellow solution. This becomes a blue, then green and finally violet solution