AL CHEM (very urgent!!!)

1. as it states that 3 reactions (3 equations) are present, you can expect that vanadium(II) is progressively oxidized to vanadium(III), oxovanadium(IV) and dioxovanadium(V) / vanadate(V).
color of (II), (III), (IV) and (V) are purple/lilac, green, blue and yellow, repsectively.

half-equation is permanganate is easy, try yourself;
V(2+) ------> V(3+) + e-
V(3+) + H2O ------> VO(2+) + 2H(+) + e-
VO(2+) + H2O ------> VO2(+) + 2H(+) + e-
OR VO(2+) + 2H2O ------> VO3(-) + 4H(+) + e-

combine them yourself.

2. reduction of vanadium(V) to vanadium(IV), followed by coproportionation of vanadium(IV) and vanadium(II).
Coproportionation: reverse of disproportionation, reaction of same element with different oxidization number, yielding same resultant O.N.
vanadium(II) + vanadium(IV) ------> vanadium(III) x2
equation should be easy.


p.s. more example of disproportionation: passing chlorine gas into sodium hydroxide solution, forming sodium chloride and sodium hypochlorite;
coproportionation: reaction of sodium chloride and sodium hypochlorite with acids, forming chlorine.