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

When $Mg_2C_3$ is reacted with water,a compound $X$ is formed which on heating with $Na$ followed by treatment with $C_2H_5Br$ gives another compound $Y$. Calculate the number of sigma bonds in $Y$.

Choose the correct set of reagents for the following conversion:
$trans-(Ph-CH=CH-CH_3) \rightarrow cis-(Ph-CH=CH-CH_3)$

The reagents to carry out the following conversion are:

Which is the most suitable reagent among the following to distinguish compound $(iii)$ from the rest of the compounds?
$(i)$ $CH_3-C\equiv C-CH_3$
$(ii)$ $CH_3-CH_2-CH_2-CH_3$
$(iii)$ $CH_3-CH_2-C\equiv CH$
$(iv)$ $CH_3-CH=CH_2$

Give the main product of the following reactions:
$(i)$ $1,1,2,2-$tetrabromopropane + zinc powder in methanol.
$(ii)$ Reaction occurring on passing hydrogen gas through carbon electrodes at high temperature in an electric arc.