Video Transcript
Which of the parts of this
5-hexen-3-ol derivative indicates that the molecule is unsaturated? (A) 1, (B) 2, (C) 3, (D) 4, or (E)
5.
To answer this question we need to
know what unsaturated means. Unsaturated hydrocarbons are
hydrocarbons that have at least one double or triple bond between adjacent carbon
atoms. In contrast, saturated hydrocarbons
are hydrocarbons that only consist of single covalent bonds between carbon
atoms.
In this question, we’ve been given
the skeletal structure of a derivative of 5-hexen-3-ol, and we need to determine
which of the circled parts indicates that the molecule is unsaturated. Firstly, we need to recognize that
in a skeleton formula, the points at which line segments meet and the end of line
segments each represent a carbon atom.
With this in mind, let’s take a
look at part 1. This section represents a single
bond between two carbon atoms. Part 2 is an OH group or a hydroxy
group. This group consists of an oxygen
atom single bonded to a hydrogen atom. Part 3 is another carbon–carbon
single bond. In part 4, there are two lines
between the carbon atoms. This represents a carbon–carbon
double bond. Lastly, part 5 is a chlorine atom,
also called a chloro group.
If we look back at the definitions
of unsaturated and saturated hydrocarbons, we see that the main difference between
them is that an unsaturated hydrocarbon contains at least one carbon–carbon double
or triple bond. Therefore, this molecule is
unsaturated because it contains a carbon–carbon double bond.
So the part of the 5-hexen-3-ol
derivative that indicates that the molecule is unsaturated is part 4, answer choice
(D).
