Question

Which of the following statement is correct?

• A. Methane and Iso-pentane are successive homologues.
• B. Iso-butane and Iso-heptane are successive homologues.
• C. Octane and Nonane are successive homologues.
• D. All of the above.

Answer 1

The correct option is C Octane and Nonane are successive homologues.

$\text{Octane}{C}_8{H}_{18}$
$\text{Nonane}{C}_9{H}_{20}$
Homologous series :
A group or a series of organic compounds each containing a characteristic functional group forms a homologous series.
Successive homologues differ by $-C{H}_2$ only
For example,
$\text{Methane}C{H}_4$
$\text{Ethane}{C}_2{H}_6$
Both are successive homologues since ethane differs from methane by $-C{H}_2$ only
Similarly in option (c) $\text{Octane}{C}_8{H}_{18}$
$\text{Nonane}{C}_9{H}_{20}$
both are successive homologues as Nonane has one $-C{H}_2$ group extra.