The reaction of vinyl chloride with $HCl$ yields ...... .

Predict the order of reactivity of the following compounds in $S_{N}1$ and $S_{N}2$ reactions:
$(i)$ The four isomeric bromobutanes
$(ii)$ $C_{6}H_{5}CH_{2}Br$,$C_{6}H_{5}CH(C_{6}H_{5})Br$,$C_{6}H_{5}CH(CH_{3})Br$,$C_{6}H_{5}C(CH_{3})(C_{6}H_{5})Br$

The ${S_{N}2}$ reaction of an asymmetric carbon compound always gives:

Out of $C_{6}H_{5}CH_{2}Cl$ and $C_{6}H_{5}CHClC_{6}H_{5},$ which is more easily hydrolysed by aqueous $KOH$?

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 major product formed when $1$-Bromo-$3$-chlorocyclobutane reacts with metallic sodium in dry ether is