Video Transcript
Which of the following is the
formula of 2-methylpropan-2-ol?
To answer this question, we need to
determine which of the molecular structures corresponds to the provided IUPAC
name. Let’s start by breaking the name
into components and considering each one at a time.
“Propan” is the stem term. We can use the stem term to
determine the length of the longest continuous chain of carbon atoms in the molecule
and the type of bonds between the carbon atoms. Prop- indicates that the longest
continuous chain of carbon atoms is three carbon atoms long, and A-N tells us that
the carbon atoms are single bonded together. So we can begin to draw a structure
for this molecule by single bonding three carbon atoms in a chain.
Now let’s look at the suffix
O-L. O-L indicates that the primary
functional group of this molecule is an alcohol. So a hydroxy group, an oxygen atom
bonded to a hydrogen atom, will be present in the structure. The two in front of O-L tells us
which carbon atom of the chain the hydroxy group is bonded to. So in the structure, we can draw a
bond between the second carbon atom of the chain and a hydroxy group.
Now let’s look at the term
methyl. Meth- indicates that this group
contains one carbon atom, while Y-L tells us that this carbon atom is a
substitutant, a group that is not a part of the main chain. Once again, the number two tells us
that this group is bonded to the second carbon atom of the chain. So in our structure, we can draw a
bond between the second carbon atom of the chain and a new carbon atom.
We’ve identified all of the
components of the IUPAC name, but the structure is still missing something. Carbon atoms should form a total of
four bonds, but these carbon atoms only have one bond each. Therefore, each of these carbon
atoms must also be bonded to three hydrogen atoms.
We have now completed the structure
of 2-methylpropan-2-ol. Looking at the answer choices, we
can see that the structure we have drawn matches the one shown in answer choice
(C). So the correct formula of
2-methylpropan-2-ol is the structure shown in answer choice (C).
