Everything Science Grade 12

CHAPTER 1. ORGANICMOLECULES 1.8

the alkane ’propane’).

Step 3 : Number the carbons inthe carbon chain

In this case, it doesn’t matter whether you start numbering from

the left or right. The hydroxyl group will still be attached to the

middle carbon atom, numbered ’2’.

Step 4 : Look for any branchedgroups, name them andgive their posi-

tion on the carbon chain.

There are no branchedgroups in this compound, but you still

need to indicate the position of the hydroxyl group on the second

carbon. The suffix willbe -2-ol because the hydroxyl group is

attached to the second carbon.

Step 5 : Combine the elements of the compound’s name into a single

word in the order of branched groups; prefix; name ending according to

the functional group.

The compound’s nameis propan-2-ol.

Example 10: Naming alcohols 2

QUESTION

Give the IUPAC name for the following compound:

H C 1

OH

H

C 2

OH

H

C 3

H

H

C 4

H

H

H

SOLUTION

Step 1 : Identify the functionalgroup

The compound has an-OH (hydroxyl) functional group and is

therefore an alcohol. There are two hydroxyl groups in thecom-

pound, so the suffix will be -diol.