Identify the compound $(Z)$ in the following reaction sequence: $CH_3-CH(Br)-CH_2Br$ $\xrightarrow{alc. KOH, \Delta}$ $\xrightarrow{NaNH_2}$ $\xrightarrow{H_2O, Hg^{2+}, H^+} (Z)$

An acyclic hydrocarbon $P$ with molecular formula $C_6H_{10}$ produces acetone as the only organic product through the following reaction sequence,where $Q$ is an intermediate organic compound:
$P (C_6H_{10})$ $\xrightarrow[(ii) NaBH_4/ethanol, (iii) dil. acid]{(i) dil. H_2SO_4/HgSO_4} Q$ $\xrightarrow[(ii) O_3, (iii) Zn/H_2O]{(i) conc. H_2SO_4 (catalytic amount), (-H_2O)} 2 CH_3COCH_3$
$1.$ The structure of compound $P$ is:
$(A)$ $CH_3CH_2CH_2CH_2-C \equiv C-H$
$(B)$ $H_3CH_2C-C \equiv C-CH_2CH_3$
$(C)$ $(CH_3)_2CH-C \equiv C-CH_3$
$(D)$ $(CH_3)_2CH-C \equiv C-H$
$2.$ The structure of compound $Q$ is:
$(A)$ $(CH_3)_2CH-CH(OH)-CH_2CH_3$
$(B)$ $(CH_3)_2CH-CH(OH)-CH_3$
$(C)$ $(CH_3)_2CH-CH_2CH(OH)CH_3$
$(D)$ $CH_3CH_2CH_2CH(OH)CH_2CH_3$
Identify the correct options for $1$ and $2$.

What product is obtained by the oxymercuration of $1$-butyne using $HgSO_4 + H_2SO_4$?

What is the product formed when two molecules of $HBr$ are added to $CH_3 - C \equiv CH$?

The major product formed in the following reaction is $CH_3-C \equiv C-CH_3 + Na \xrightarrow{liquid \ NH_3}$

The product $(C)$ of the above reaction is:
Maleic anhydride $\xrightarrow{H_3O^+}$ $(A)$ $\xrightarrow{NaOH}$ $(B)$ $\xrightarrow{\text{Kolbe electrolysis}}$ $(C)$