text: These functional groups can be added to aromatic compounds by reacting carbon monoxide with hydrochloric acid and aluminum trichloride.
full_question: These functional groups can be added to aromatic compounds by reacting carbon monoxide with hydrochloric acid and aluminum trichloride. Sugars with this functionality are considered reducing sugars. Unlike the Jones reagent, PCC forms one of these functional groups from primary alcohols by not fully oxidizing them to carboxylic acids. Reacting a Grignard reagent with one of these compounds forms a secondary alcohol. These compounds form a silver mirror when reacted with Tollens' reagent. Compounds with this functional group have names ending with -anal ["uh-NAL"]. For 10 points, name this functional group that is a terminal carbonyl.
first_sentence: These functional groups can be added to aromatic compounds by reacting carbon monoxide with hydrochloric acid and aluminum trichloride.
raw_answer: aldehydes [prompt on "carbonyl" until it is read]