Isopropyl alcohol is commonly known as rubbing alcohol. What is the IUPAC name of this alcohol?

• A. $\mathrm{methanol}$
• B. $1-\mathrm{propanol}$
• C. $\mathrm{ethanol}$
• D. $2-\mathrm{propanol}$

Answer: (D)

Verified step by step guidance

1. Identify the structure of isopropyl alcohol: it consists of a three-carbon chain with a hydroxyl group (-OH) attached to the second carbon atom.
2. Recall that the IUPAC naming system for alcohols involves naming the longest carbon chain containing the hydroxyl group and numbering the chain so that the -OH group gets the lowest possible number.
3. Since the longest chain has three carbons, the base name is 'propanol'.
4. Number the carbon chain from the end nearest the hydroxyl group, placing the -OH on carbon 2, which gives the name '2-propanol'.
5. Confirm that '2-propanol' is the correct IUPAC name for isopropyl alcohol, distinguishing it from '1-propanol' where the -OH is on the first carbon.