When acetylene is passed into dilute sulphuric acid containing $Hg^{2+}$ ions,the product formed is

$CH_3-CH(CH_3)-C \equiv CH \xrightarrow{excess \ HBr}$
The product of the above reaction is

What will be obtained by the reaction of calcium carbide with heavy water? Give its chemical equation.

Complete the following reactions:
$(1)$ $CH \equiv CH + 2H_2 \xrightarrow[523-573 \ K]{Ni} ?$
$(2)$ $CH_3-C \equiv CH + 2H_2 \xrightarrow[or \ Ni, \Delta]{Pd \ or \ Pt} ?$

Write structures of different isomers corresponding to the $5^{th}$ member of alkyne series. Also write $IUPAC$ names of all the isomers. What type of isomerism is exhibited by different pairs of isomers?

The most suitable reagent for the following conversion is:
$H_3C-C \equiv C-CH_3 \rightarrow \text{cis-2-butene}$