Question

Which has the fast reaction with KOH (aq)
A.
B.
C.
D.

Answer 1

The unstable compounds only undergo reaction with KOH. If the compound is going to get resonance because of the neighboring atoms then the compound is more stable than the ordinary organic compound.

Complete answer:
- In the question it is given to find the compound which is going to react with KOH among the given options.
- Coming to the given options, option A.

- If the chlorine atom comes out from the given organic compound we will get the following structure.

- Now we can see clearly that no neighbor atom existed to stabilize the cationic species which is produced from the compound A.
- Therefore compound A is going to react with KOH.
- Coming to option B,

- If the chlorine atom comes out from the given organic compound we will get the following structure.

- The cation which is produced by the liberation of the chlorine atoms is stabilized by the neighboring nitrogen atom.
- Therefore the compound B is stable and won’t react with KOH.
- Coming to option C,

- If the chlorine atom comes out from the given organic compound we will get the following structure.

- The cation which is produced by the liberation of the chlorine atoms is stabilized by the neighboring nitrogen atom.
- Therefore the compound B is stable and won’t react with KOH.
- Coming to option D,

- If the chlorine atom comes out from the given organic compound we will get the following structure.

- The cation which is produced by the liberation of the chlorine atoms is stabilized by the neighboring nitrogen atom.
- Therefore the compound B is stable and won’t react with KOH.

So, the correct option is A.

Note:
If the cation which formed by the liberation of the halide is going to get stability due to the electron donation of the neighboring groups then the molecule is more stable than the normal compounds which do not have the neighboring group which donate electrons.