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

Among the given halides,which one will give the same product in both $S_{N^1}$ and $S_{N^2}$ reactions?
$(I) \ CH_3-CH(CH_3)-CH_2-CH(Br)-CH_3$
$(II) \ \text{2-methylcyclohexyl chloride}$
$(III) \ \text{Chlorocyclohexane}$
$(IV) \ CH_3-CH(Br)-CH_2-CH_3$

Compound $C_4H_8Cl_2$ $(A)$ on hydrolysis gives a compound $C_4H_8O$ $(B)$ which reacts with hydroxylamine and does not give any test with Tollen's reagent. What are $(A)$ and $(B)$?

The reaction of $t-$butyl bromide with sodium methoxide mainly gives .............

Heterolytic bond dissociation energy of alkyl halides follows the sequence:

In which of the following is the carbon-halogen bond strongest?