Which reaction is not possible?

When vinyl and allyl radicals are joined together,we get:

The gas liberated at the anode by the electrolysis of a concentrated aqueous solution of dipotassium succinate is:

The reaction of $4$-methyloct$-1-$ene $(P, 2.52 \ g)$ with $HBr$ in the presence of $(C_6H_5CO_2)_2O_2$ gives two isomeric bromides in a $9:1$ ratio,with a combined yield of $50 \%$. Of these,the entire amount of the primary alkyl bromide was reacted with an appropriate amount of diethylamine followed by treatment with aqueous $K_2CO_3$ to give a non-ionic product $S$ in $100 \% $ yield. The mass (in $mg$) of $S$ obtained is. . . . . . . [Use molar mass (in $g \ mol^{-1}$) : $H=1, C=12, N=14, Br=80$]

Hardening of oil is done by

The major product $(P)$ formed in the reaction below is: $HC \equiv C-CH_2-CH=CH_2 \xrightarrow[CCl_4, 253 \ K]{Br_2(1 \ mol)} P$