Which type of compound is defined by having oxygen connected to two carbon chains?

• A. Alcohol
• B. Carboxylic acid
• C. Ester
• D. Ether

Answer: (D)

The key idea is recognizing how oxygen bonds to other atoms in a functional group. An ether has oxygen bonded to two carbon groups (R–O–R′), with the oxygen making two single bonds to carbon and no hydrogen attached to it. This distinct arrangement sets ethers apart from other oxygen-containing classes: alcohols have the oxygen attached to one carbon and one hydrogen (R–O–H), carboxylic acids feature a carbonyl carbon (C=O) with an OH group (R–COOH), and esters have oxygen connected to a carbonyl carbon (R–CO–O–R′). So “oxygen connected to two carbon chains” fits the ether structure, with a concrete example like diethyl ether, CH3CH2–O–CH2CH3.