Hydrocarbon $(A)$ reacts with bromine by substitution to form an alkyl bromide,which by Wurtz reaction is converted to a gaseous hydrocarbon containing less than four carbon atoms. $(A)$ is

Which of the following is a correct reaction?

The alkane which is next to methane in the homologous series can be prepared from which of the following reactions?
$I$. $2 CH_3 Br \xrightarrow[\text{dry ether}]{Na}$
$II$. $CH_3 COOH \xrightarrow[CaO, \Delta]{NaOH}$
$III$. $CH_3 CH=CH_2 \xrightarrow{H_2 / Pt}$
$IV$. $CH_3 CH_2 Br \xrightarrow[H^{+}]{Zn}$
Correct answer is

An alkane forms isomers if the number of carbon atoms is at least

Identify substrate '$S$' in the following reaction: $S \xrightarrow{Na / \text{dry ether}} 3, 4-\text{diethyl}-3, 4-\text{dimethylhexane}$

Which of the following formulas represents a saturated cyclic compound?