What is the end product of the following sequence of operations?
$CaC_2$ $\xrightarrow{H_2O} A$ $\xrightarrow[Hg^{2+}]{dil. H_2SO_4} B$ $\xrightarrow[H_2]{Ni} C$

Number of $\sigma$ and $\pi$ bonds present in $but-1-ene-3-yne$ respectively are

Which one is the correct order of acidity?

Hex$-1-$yne on reaction with $Br_2$ (excess)/ $CCl_4$,gives

Which of the following metal carbides gives propyne on hydrolysis?

An unsaturated hydrocarbon $X$ on ozonolysis gives $A$. Compound $A$ when warmed with ammoniacal silver nitrate forms a bright silver mirror along the sides of the test tube. The unsaturated hydrocarbon $X$ is ..... .