(N/A) Hydrohalogenation of alkynes: Alkynes undergo electrophilic addition reactions with hydrogen halides ($HCl$,$HBr$,$HI$). Two molecules of hydrogen halide add to the alkyne to form a gem-dihalide,where both halogen atoms are attached to the same carbon atom.
$(b)$ Hydration of alkynes: Hydration involves the addition of water $(H_{2}O)$ in the presence of a catalyst (e.g.,$HgSO_{4}/H_{2}SO_{4}$). The reaction proceeds via electrophilic addition. First,the electrophilic $H^{+}$ from $H_{2}O$ adds to the triple bond according to Markovnikov's rule to form a stable carbocation. Subsequently,the $OH^{-}$ ion adds to form an enol (alkenol),which then undergoes tautomerization (isomerization) to form a stable aldehyde or ketone containing the $>C=O$ group.