[Fry]

Why is an acid catalyst used in this synthesis?

One source (http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=cv2p0071) tells me that its used to remove trace amounts of alkali that would reduce the benzaphenone to benzohydrol..


But im told its being used as a catalyst, or is my definition not right? do the proton and the conjugate acetate ion stabilize the intermediate n,pi* radicals?