Question

The organic compound, which gives a red precipitate with ammoniacal cuprous chloride and undergoes an addition reaction, is:
A. Ethane
B. Ethene
C. Ethyne
D. Ethanol

Answer 1

Hint- In order to deal with this question first we will understand the addition reaction, we will first look for the compound that gives red precipitate with ammoniacal cuprous chloride reaction further we will write the proper reaction of acetylene and ammoniacal cuprous chloride reaction in order to check the product and see the addition reaction.

Complete step-by-step answer:
Addition reaction: A chemical reaction is an addition reaction in which two or more reactants come together to form a larger composite component. But only chemical compounds with multiple bond characteristics may undergo an additional reaction, since normally a double or triple bond is broken to form the necessary single bonds.
So from the above understanding, ethane and ethanol cannot be the answer. Out of ethane and ethyne, ethyne undergoes additional reaction with ammoniacal cuprous chloride which will be shown further.
Ethyne is also called acetylene.
Reaction with ammoniacal cuprous chloride solution:- When acetylene is passed through ammoniacal cuprous chloride solution, a red precipitate of copper acetylide is formed as shown in the given reaction.
\[H - C \equiv C - H + C{u_2}C{l_2} + 2N{H_4}OH \to Cu - C \equiv C - Cu + 2N{H_4}Cl + 2{H_2}O\]
In the above reaction \[Cu - C \equiv C - Cu\] formed in the product side is copper acetylide and is the red precipitate as mentioned in the question.

Hence, ethyne gives a red precipitate with ammoniacal cuprous chloride
So, the correct answer is option C.

Note- An additional reaction is basically a reverse reaction to decomposition in which a reaction to decomposition is a reaction in which one combines one or more elements or compounds. The Aromatic Compound is acetylene. This is the simplest alkyne and a hydrocarbon. This colorless gas is commonly used as fuel and building material for chemicals. In its pure nature, it is unstable.