Question

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?

Answer 1

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:

`DU= C-H/2+N/2-X/2+1`

Where `DU` 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`, `DU` would be:

`DU= 4-8/2+0/2-0/2+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: