What is the IUPAC name for the following compound? HC$\equiv$CCH$_{3}$

Analysis

The question asks for the IUPAC name of the hydrocarbon with the structural formula HC$\equiv$CCH$_{3}$.

Concept

To name this compound, we look at the functional group present:

1. Functional Group: The triple bond ($\equiv$) indicates that this compound belongs to the alkyne family.
2. Carbon Chain Length: There are 3 carbon atoms in the chain. The prefix for 3 carbons is "prop-".
3. IUPAC Naming Rule: For alkynes, the suffix is "-yne". Therefore, the systematic IUPAC name is propyne.

Solution

Let's evaluate the options provided:

• A. Acetylene: This is the common name for ethyne ($HC\equiv CH$), not the compound in the question.
• B. Methyl acetylene: This is the common name for propyne. While it is not the systematic IUPAC name (which is propyne), in many JAMB past questions, this is often the intended answer when "propyne" is not listed as an option.
• C. Butanol: This is an alcohol (contains an -OH group), which is incorrect.
• D. Decanoic acid: This is a carboxylic acid, which is incorrect.

In the context of older or specific JAMB question banks, common names are sometimes accepted as the IUPAC name for simple hydrocarbons.

Tip

When naming hydrocarbons, always count the longest carbon chain first. If you see a triple bond, look for the "-yne" suffix. If the systematic name isn't there, look for the common name that describes the structure (like "methyl" attached to "acetylene").