Cumene on oxidation in air gives a compound, $X$. This on reaction with dilute acid gives $Y$ and $Z . Y$ reacts with sodium metal and not $Z$. What is $Z$ ?

Arrange the following in decreasing order of their boiling points

(A) 2-methylbutane

(B) 2, 2-dimethyl propane

(C) Pentane

(D) Hexane

An alkyne has the molecular formula $\mathrm{C}_6 \mathrm{H}_{10}$. The number of 1 -alkyne isomers (excluding stereoisomers) possible for it is

Dehydration of an organic acid $X$ with concentrated $\mathrm{H}_2 \mathrm{SO}_4$ at 373 K gives $\mathrm{H}_2 \mathrm{O}$ and gas $Y$. The hybridisation of the carbon in $Y$ and nature of $Y$ are respectively.