A carbonyl group (double bond oxygen to a carbon) is found on several functional groups: aldehydes, ketones, amides, and carboxylic acids. In aldehydes, the carbonyl group is on the primary carbon, at end of a carbon chain, while in ketones, it is on a secondary carbon, in the middle of a carbon chain. The double bond in the carbonyl group is very susceptible to chemical reactions, specifically, oxidation and reduction reactions and the formation of hemiacetals and acetals. The names of aldehydes and ketones are simply derived by dropping “-e” from the root and adding “-al” or “-one” respectively. A position number is needed for ketones since the carbonyl group may be on any number of several carbons in the middle of a chain. For example, propanone also known as acetone is primarily a solvent since it dissolves in both water and non-polar organics; however, it may also be present in the urine of diabetics. It is also frequently used in fingernail polish remover. The carbonyl on the aldehyde is always on the number one carbon so no position number is needed. For example, methanal also known as formaldehyde is used to synthesize methanol and many plastics such as Bakelite and Melmac. In addition to its antiseptic properties, formaldehyde has also been used in embalming and preservation of biological specimens.