Question

Ethylidene chloride reacts with aqueous KOH to form which of the following compounds?
A.) Acetaldehyde
B.) Ethylene glycol
C.) Ethyl alcohol
D.) Acetic acid

Answer 1

Hint: Aq KOH is alkaline in nature. Hence it gives hydroxide ions which act as strong nucleophile and replace the halogen atom (Cl in this question) from alkyl halide which results in the formation of alcohol molecules and hence the reaction is referred to as Nucleophilic substitution reaction and further reaction leads to the product.

Complete step-by-step answer:
Reaction of alkyl halide with aq KOH -

$C{H_3}CHC{l_{_2}}\xrightarrow[{aq}]{{KOH}}\,C{H_3}\,CH{\left( {OH} \right)_2} \to C{H_3}CHO\, + {H_2}O$

When Alkyl halide is treated with aq KOH, alcohol is obtained, and then further reaction takes place which results in the formation of an aldehyde.

Acetaldehyde is the byproduct of the reaction.

Ethylidene chloride reacts with propylene glycol in the presence of aqueous KOH to form Acetaldehyde.
Hence, the solution is option A – Acetaldehyde.

Aqueous KOH is alkaline in nature and dissociates to produce a hydroxide ion. These hydroxide ions being very strong nucleophiles replace the halogen atom in alkyl halide resulting in the formation of alcohol molecules and the reaction is known as nucleophilic substitution reaction.

Generally, aqueous KOH is used for reactions that are not water sensitive and while performing a hydrolysis. Saponification of amides and esters are two examples when aqueous KOH is preferred (as they are hydrolysis reactions).

Acetaldehyde is one of the most necessary aldehydes in chemistry, occurring widely in nature and being produced on a large scale in industry too. It also occurs naturally in coffee, bread, and ripe fruit, and is produced by plants too.
Acetaldehyde is the most frequently found air infiltrate with cancer risk more than one in a million.

Note: When Alkyl halide is treated with aq KOH, alcohol is obtained (nucleophilic substitution), and then further reaction takes place which results in the formation of an aldehyde.