Ethylene difluoride on hydrolysis gives

In the above reaction,the major product '$P$' is:

The correct reactivity order for $S_N2$ reaction is:
$(i)$ $CH_3COCH_2Cl$
(ii) $CH_2=CH-CH_2Cl$
(iii) $CH_3CH_2CH_2Cl$

Among the following,the one which reacts most readily with ethanol is

Arrange the following in order of ease of dehydrohalogenation:
$(i)$ Bromocyclohexane
(ii) $3-$Bromocyclohexene
(iii) $3-$Bromocyclohexa$-1,4-$diene
(iv) Bromobenzene

$A$ solution of $(+)-1$-chloro-$1$-phenylethane in toluene racemizes slowly in the presence of a small amount of $SbCl_5$ due to the formation of which of the following?