I'm curious, for an infrared (IR) spectrum for diphenylacetic acid, why isn't there any broad peak for the OH? There's nothing of interest above 3000 cm^-1. I looked it up on SDBS and it looks the same there too so my textbook can't be lying to me. At first I thought it was because of the symmetry relationship, but if that's true, then why won't the peak at ~1700 cm^-1 disappear too?