Which of the following has the highest boiling point?

The catalyst used for the isomerisation of $n$-alkanes to branched chain alkanes is

$A$ hydrocarbon of molecular mass $72 \ g \ mol^{-1}$ gives a single monochloro derivative and two dichloro derivatives on photochlorination. Give the structure of the hydrocarbon.

What is the product of the following reaction?
$p-CH_3C_6H_4MgBr + CH_3CH_2OH \rightarrow ?$

$X$ is an isomer of $C_6H_{14}$. It has four primary carbons and two tertiary carbons. '$X$' can be prepared from which of the following reactions?

Acetic acid is reacted with metallic sodium to form hydrogen and $X$. When $X$ is heated with sodalime,$Y$ and sodium carbonate are formed. $Y$ is