$CaC_2$ reacts with $H_2O$ to produce ...... .

$C_6H_5 - C \equiv C - CH_3 \xrightarrow{HgSO_4, H_2SO_4} A$

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

$A$ bromoalkane is reacted with the sodium salt of an alkyne to obtain $3$-octyne. What are the bromoalkane and the alkyne respectively?

An alkyne has the molecular formula $C_6H_{10}$. The number of $1$-alkyne isomers (excluding stereoisomers) possible for it is

Acetylenyl hydrocarbons are acidic because ..