Variable Oxidation States

what happens when adding zinc and acid to vanadium

can reduce vanadium step by step from vanadium (V) to vanadium (II).

what observations when zinc and acid is added to vanadium

we observe a series of colour changes known as the ‘vanadium rainbow’. 

yellow (V(V)), blue (V(IV)), green (V(III)), and violet (V(II)). 

the overall equation for the reaction for Vnadium reaction

2VO₂⁺+8H⁺+3Zn→2V²⁺+4H₂O+3Zn³⁺

explain zinc and vanadium reaction usiing electrode potentials

We can calculate the final oxidation state of vanadium during a reduction reaction by focussing on the number of electrons that are transferred from the reducing agent. 

where does the highest oxidation state occur for Manganese

MnO₄^-

^{oxidation state +7}

reaction of Manganate ion and Fe²⁺

MnO4−(aq)+5Fe2+(aq)+8H+(aq)→Mn2+(aq)+5Fe3+(aq)+4H2O (l)

reaction of Manganate ions and C₂O₄^2-

2MnO4−(aq)+5C2O42−(aq)+16H+(aq)→Mn2+(aq)+10CO2(aq)+8H2O (l)

Colour change in redox reaction for Manganate ions

Magnate ions purple in solution once fully used up change to colourless

How to work out redox titration calculations

same as acid-base reaction

1. They often involve taking samples, so you need to account for this in your calculations.

how to calculate % purity

%purity of substance x=( mass of x in the sample /total mass of the sample) ×100

mole ratio between reactants