Which one of the following does not give white precipitate with acidified silver nitrate solution-

Options

A.
B. `CH_(2)=CH-Cl`
C. `CH_(2)=CH-CH_(2)-Cl`
D. both A and B

Answer

D

Explanation

A `sp^(2)`- hybridised carbon atom is more electronegative than a `sp^(3)`-hybridised carbon atom due to greater s-character. Therefore, the `sp^(2)` - hybridised carbon atom of C-Cl bond in chlorobenzene has very less tendency to donate C-Cl bond pair electrons. Further due to delocalisation of lone pair of electrons of Cl-atom over the benzene ring, C-Cl bond in chlorobenzene gets partial double bond character.

Vinyl chloride `(CH_(2)=CHCl)` is unreactive in `S_(N)2` reaction due to resonance.

In vinly chloride, the lone pair of electrons on chlorine is in resonance with C=C double bond. Hence, there is partial doubled bond character in C-Cl bond. As a result , removal of `CI^(Theta)` is no fesible here.
Further, due to greater stabilisation of allylic carbocation intermediate by resonance, chlorine can easily be eliminated from `CH_(2)=CH-CH_(2)-Cl` and gives white precipitate with acidified `AgNO_(3)` solution
.