The homologue of ethyne is

Identify $Z$ in the following sequence:
$C_3H_7OH$ $\xrightarrow{H_2SO_4} X$ $\xrightarrow{Br_2} Y$ $\xrightarrow{KOH} Z$

Propyne reacts with excess $HBr$ to form the compound $Z$. The structure of $Z$ is:

Identify the product $D$ in the following series of reaction: $CH_3COOH$ $\xrightarrow{LiAlH_4} A$ $\xrightarrow{H^{+}, 443 \ K} B$ $\xrightarrow{Br_2} C$ $\xrightarrow{alc. KOH} D$

Cyclo$[18]$ carbon is an allotrope of carbon with molecular formula $C_{18}$. It is a ring of $18$ carbon atoms,connected by alternating single and triple bonds. The total number of triple bonds present in this cyclocarbon is:

Which of the following organic compounds has the same hybridization as its combustion product $(CO_2)$?