What is the limiting reactant when 3 moles of A and 4 moles of B are allowed to react? 2A 2B-3C

Is that your equation? :confused:

If so, then you know that you need 2 moles of A and two moles of B for complete reaction with no leftovers.

That means, that the amount of A and B should be equal. But in your given, one is more than the other. The lesser one is the limiting reagent. What is it?

Consider the following reaction:

A + 2B =====> C

If you have 5 mols of B react with an excess of A, what is the maximum number of moles of C that you can produce?