Which of the following carbides will produce propyne on hydrolysis?

The major product of the following reaction is:

Which is the most suitable reagent among the following to distinguish compound $(3)$ from the others?
$(1) \ CH_3-C \equiv C-CH_3$
$(2) \ CH_3-CH_2-CH_2-CH_3$
$(3) \ CH_3-CH_2-C \equiv CH$
$(4) \ CH_3-CH=CH_2$

Write the following reactions:
$1$. Complete combustion of ethyne in the presence of air.
$2$. Reaction of propyne with alkaline $KMnO_4$.

$1, 2-$dibromoethane when heated with alcoholic potash gives

$A$ salt-producing hydrocarbon among these compounds is