Question

Name the following compound:

2-ethylpentane
4-ethylpentane
3-methylpentane
3-methylhexane

Answer 1

Answer : The correct option is, 2-ethylpentane

Explanation :

The IUPAC nomenclature of alkanes are :

• First select the longest possible carbon chain.
• For the number of carbon atom, we add prefix as 'meth' for 1, 'eth' for 2, 'prop' for 3, 'but' for 4, 'pent' for 5, 'hex' for 6, 'sept' for 7, 'oct' for 8, 'nona' for 9 and 'deca' for 10.
• A suffix '-ane' is added at the end of the name.
• The numbering is done in such a way that first carbon of double bond gets the lowest number.
• If two of more similar alkyl groups are present, then the words 'di', 'tri' 'tetra' and so on are used to specify the number of times these alkyl groups appear in the chain.

Hence, the name for given compound will be, 2-ethylpentane and the structure are shown below.

Answer 2

3-methylhexane

Step-by-step explanation:

The compound is 6 carbon atoms long, a hexane. It branches with a methyl group on the third carbon group.

This makes it a 3-methylhexane