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.

(N/A) $(i)$ The reaction of $1,1,2,2-$tetrabromopropane with zinc powder in methanol is a dehalogenation reaction that produces propyne:
$CH_3CBr_2CHBr_2 + 2Zn \rightarrow CH_3C \equiv CH + 2ZnBr_2$
$(ii)$ The reaction of hydrogen gas with carbon in an electric arc at high temperature $(3270 \ K)$ produces ethyne (acetylene):
$2C + H_2 \xrightarrow{\text{Electric arc}, 3270 \ K} HC \equiv CH$