I am most probably incorrect in my assumption that sulfuric acid completely and perfectly dissociates.

Good point. While assumption that first proton is completely dissociated holds even in highly concentrated solutions, HSO

_{4}^{-} is a relatively weak acid.

However, if we know the number of mols of H+ to be 0.00328984 mols, and we know the solution to be essentially 50 mL, why is the answer not -log(0.00328984/50), or about 4.18?

Even assuming complete dissociation of sulfuric acid molarity of H

^{+} would be not 0.00328984/50 - for two reasons. First, amount of H

^{+} is not 0.00328984 moles, second, volume is not 50 L.

Come on folks, it is Friday - not much time till the next problem - and we are not done with this one yet!