Balance the following equation for a half reaction that occurs in acidic solution. Use e– as the symbol for an electron.

Question

Mo^3+ -> MoO2^2+

Answer 1

Here you can find all you ever wanted to know about redox equations.
http://www.chemteam.info/Redox/Redox.html

Here is a hint to help get you started.
Mo changes from +3 on the left to +6 on the right.