Question

What is the reducing agent in the following reaction below 2mno4 + br-?

Answer 1

Now, the first thing to do is work out the oxidation states of the elements in the equation.
I'll work out one for you.
MnO4- — 4(-2) + x = -1
x = +7
Here, -2 is oxidation no of oxygen and x is for Mn.

MnO2 — Mn is +4 here.

So you can see the Mn in MnO4- REDUCED from +7 to +4.
The molecule thats reduced is your oxidising agent.
So if Mn is reduced, something must've been oxidised right?

Take a look at Br.
BrO3- — 3(-2) + x = -1
x = +5
Br is +5.