The catalyst used in the dimerization of acetylene to prepare chloroprene is:

Which of the following reagents is most suitable to distinguish compound $(3)$ from the others?
$(1) \ CH_3-C \equiv C-CH_3$
$(2) \ CH_3CH_2CH_2CH_3$
$(3) \ CH_3CH_2C \equiv CH$
$(4) \ CH_3CH=CH_2$

The reagent needed for converting $Ph-C \equiv C-Ph$ to trans-stilbene is:

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:

$CH \equiv CH$ $\xrightarrow{O_3/NaOH} X$ $\xrightarrow{Zn/CH_3COOH} Y$. '$Y$' is:

Number of acidic hydrogen atoms in $but-1-yne$ are