The treatment of alkyl halides with alcoholic KOH leads to the formation of alkenes. Justify.

Explanation

`underset("Ethyl bromide")(C_2 H_5 Br + K^(+) : underset(* *) overset(* * )O - overset(* *)O : to underset("Ethyl nitrite (Main product)")(C_2 H_5 - overset(* *)O - overset(* * )N = overset(* * )O : +KBr)`
In this rcaction some nitroetirane is also formed. It is due to anbidentate nature of nitrite ion

Reason : `KNO_2` is predominantly ionic and provides nitrite ions `( : underset*(* * )overset(* * )O- overset(* * )N= overset(* * )O : )` in solution, Although both nitrogen and oxygen atoms are in a portion to donate electron pairs, the attack takes place mainly through oxygen atom since oxygen atom carries a negative charge also. However `AgNO_2` in mainly covalent in nature and nitrogen being less electronegative than oxygen can easily. donate electron pair forming nitroethane as the main product