In the following series of chemical reactions,identify $Z$.
$C_3H_7OH$ $\xrightarrow[160-180\,^{\circ}C]{Conc. H_2SO_4} X$ $\xrightarrow{Br_2} Y$ $\xrightarrow{Excess \ of \ Alc. KOH} Z$

$CH_3-C\equiv CH \xrightarrow{O_3/Zn, H_2O_2} \text{Product}$ The product in the above reaction is

In the reaction $CH_3-CH_2-C \equiv CH + HCl \to B \xrightarrow{HI} C$,what is the product $C$?

What is the product when acetylene reacts with hypochlorous acid $(HOCl)$?

$But-2-yne$ and hydrogen (one mole each) are separately treated with $(i)$ $Pd / C$ and $(ii)$ $Na / \text{liq. } NH_3$ to give the products $X$ and $Y$ respectively. Identify the incorrect statements.
$A$. $X$ and $Y$ are stereoisomers.
$B$. Dipole moment of $X$ is zero.
$C$. Boiling point of $X$ is higher than $Y$.
$D$. $X$ and $Y$ react with $O_3 / Zn + H_2O$ to give different products.
Choose the correct answer from the options given below:

Identify $A$ in the following reaction.
$A$ $\xrightarrow{\text{Lithium amide}} \text{Ethynyl lithium}$ $\xrightarrow{\text{Bromoethane}} \text{but-}1\text{-yne}$