How do you balance oxidation reduction reactions in basic solution?
The same way as you balance redox equations in acid media; but there is a useful trick.
A general method for balancing redox reactions is given here. But let's suppose that you were asked to represent the reduction of
We could first represent the reduction in acidic media:
Now this reduction reaction is balanced with respect to mass and charge, as it must be. However, basic conditions were specified, so we have to try to remove the
Which is clearly balanced with respect to mass and charge as required. Possibly the following equation makes more chemical sense:
In that most hydroxides are insoluble. Is charge still balanced here?
So I have made a meal of this, but my advice is to balance the redox equation using acid conditions, and at the end to represent redox in basic conditions add appropriate equivalents of hydroxide, and remember to cancel the waters out on each side.