Which among the following compounds is a gem-dihalide?

Nitrobenzene at room temperature is

Which of the following are vinyl chlorides?
$(a)$ $3\text{-chlorocyclohexene}$
$(b)$ $1\text{-chlorocyclohexene}$
$(c)$ $4\text{-chlorobut-1-ene}$
$(d)$ $1\text{-chloroethene}$
$(e)$ $3\text{-chlorobut-1-yne}$
$(f)$ $3\text{-chloro-2-methylpropene}$

How many benzene derivatives are possible for the molecular formula $C_7H_7Cl$?

Which among the following is a benzylic halide?

Which among the following is $NOT$ a benzylic halide?