What is the product formed when $1$-bromo-$3$-chlorocyclobutane reacts with $2$ moles of sodium in ether?

Which reaction is useful for the exchange of halogen in alkyl chloride by iodide?

Ethylene difluoride on hydrolysis gives

Consider the reactions:
$(i) \ (CH_3)_2CHCH_2Br \xrightarrow{C_2H_5OH} (CH_3)_2CHCH_2OC_2H_5 + HBr$
$(ii) \ (CH_3)_2CHCH_2Br \xrightarrow{C_2H_5O^-} (CH_3)_2CHCH_2OC_2H_5 + Br^-$
The mechanisms of reaction $(i)$ and $(ii)$ are respectively:

Consider the given reaction: $CH_3-CH=CH-CH_2-OH \xrightarrow[S_N1]{HBr} [P]$. In the given reaction,the product $[P]$ is:

Identify the major product $(P)$ in the following reaction sequence.
$(CH_3)_3 CBr$ $\xrightarrow{\text{Alcoholic } KOH, \Delta}$ $\xrightarrow{HBr} P$