# A molecular formula is C_4H_8O_2. It has a degree of unsaturation of 1. Also it has an OH group, CH_3 (sp3) group, and C=O group. What functional groups can be present?

Feb 27, 2016

Carboxylic acid, alcohol, ketone, and aldehyde

#### Explanation:

A saturated hydrocarbon is one in which there exist no double bonds and no rings within the structure. In other words, if you had a 6-carbon molecule, it would be a chain of 6 carbons and each carbon would be attached to 4 different atoms.

Conversely, an unsaturated compound WILL have a double bond, triple bond, a ring, or any combination of the three depending on the degree of unsaturation.

Degree of unsaturation can be calculated using the following equation:

$D U = C - \frac{H}{2} + \frac{N}{2} - \frac{X}{2} + 1$

Where $D U$ is the degree of unsaturation, $C$ is the number of carbons, $H$ is the number of hydrogens, $X$ is the number of halides, and $N$ is the number of nitrogens in the compound.

Based on the formula given in the problem, ${C}_{4} {H}_{8} {O}_{2}$, $D U$ would be:

$D U = 4 - \frac{8}{2} + \frac{0}{2} - \frac{0}{2} + 1 = 1$

This implies that there is one double bond, or one ring present in the molecule. Since $C = O$ is provided, this double bond is the only cause for unsaturation in the molecule.

A few possibilities given the conditions of the problem would be: