Final answer:
When two carboxylic acids undergo condensation, they form an acid anhydride through the loss of a water molecule and the combination of their acyl groups.
Step-by-step explanation:
When two carboxylic acids condense together, they form an acid anhydride. This reaction involves the loss of a water molecule and the formation of a new covalent bond between the two acyl groups. Specifically, the carbonyl group (C=O) of one acid combines with the hydroxyl group (-OH) of the other, releasing water (H₂O) and resulting in the (-C-O-C-) linkage that characterizes an anhydride. If the two carboxylic acids are the same, the result is a symmetric anhydride, while different acids yield mixed or asymmetric anhydrides.