Practicing Success

Target Exam

CUET

Subject

Chemistry

Chapter

Organic: Haloalkanes and Haloarenes

Question:

Match List I with List II

List I List II
(A) Swart's Reaction (I) \(C_6H_5NH_2 + NaNO_2 + HX + Cu_2X_2 \longrightarrow C_6H_5X + N_2\)
(B) Finkelstein Reaction (II) \(2RX + 2Na \longrightarrow R-R + 2NaX\)
(C) Sandmeyer's Reaction (III) \(RX + AgF \longrightarrow R-F + AgX\)
(D) Wurtz Reaction (IV) \(RX + NaI \longrightarrow R-I + NaX\)

Choose the correct answer from the options given below:

 

Options:

A-I, B-II, C-III, D-IV

A-I, B-III, C-II, D-IV

A-I, B-II, C-IV, D-III

A-III, B-IV, C-I, D-II

Correct Answer:

A-III, B-IV, C-I, D-II

Explanation:

The correct answer is option 4. A-III, B-IV, C-I, D-II.

List I List II
(A) Swart's Reaction (III) \(RX + AgF \longrightarrow R-F + AgX\)
(B) Finkelstein Reaction (IV) \(RX + NaI \longrightarrow R-I + NaX\)
(C) Sandmeyer's Reaction (I) \(C_6H_5NH_2 + NaNO_2 + HX + Cu_2X_2 \longrightarrow C_6H_5X + N_2\)
(D) Wurtz Reaction (II) \(2RX + 2Na \longrightarrow R-R + 2NaX\)

Let us look at each of the reactions :

A. Swarts Reaction: (III) \(RX + AgF \longrightarrow R-F + AgX\)

The Swarts reaction is commonly used to produce alkyl fluorides from alkyl chlorides or alkyl bromides. This is accomplished by heating alkyl chloride/bromide in the presence of heavy metal fluoride (silver fluoride or mercurous fluoride for example). The reaction will proceed if sodium fluoride or potassium fluoride are used, but the yield will be greatly reduced. In 1892, Frederic Jean Edmond Swarts was the first to report this phenomenon. The swarts reaction is also known as swarts fluorination. Chlorine is most commonly replaced by fluorine in organic compounds via Swarts fluorination in the presence of antimony salts, where its oxidation state is +5.

\(RX + AgF \longrightarrow R-F + AgX\)

For example:

B. Finkelstein Reaction: \(RX + NaI \longrightarrow R-I + NaX\):

The Finkelstein reaction is a Substitution Nucleophilic Bimolecular reaction (\(S_N2\) Reaction) that involves the exchange of halogen atoms. It is named after Hans Finkelstein, a German chemist.

It is an organic reaction that uses an alkyl halide exchange into another alkyl halide through a reaction wherein the metal halide salt is used. This reaction takes place in an equilibrium process by taking the advantage of poor acetone solubility in metal halide salt that is newly formed.

(C) Sandmeyer's Reaction: (I) \(C_6H_5NH_2 + NaNO_2 + HX + Cu_2X_2 \longrightarrow C_6H_5X + N_2\):

A freshly made diazonium salt solution is treated with cuprous chloride or cuprous bromide dissolved in the appropriate halogen acids to produce chloro and bromoarenes. This process is known as the Sandmeyer reaction.

The benzene diazonium salts necessary for this procedure are made by reacting an aqueous solution of sodium nitrite with an ice-cold solution of aniline that is excessively diluted in HCl at a low temperature of 273-278 K (0-5°C). The process is referred to as a diazotization reaction.

The benzene diazonium salt is utilized to make the following aryl halides:

D. Wurtz Reaction: (II) \(2RX + 2Na \longrightarrow R-R + 2NaX\):

Wurtz reaction is a coupling reaction which is developed by Charles-Adolphe and used in organic chemistry and organometallic chemistry. Wurtz reaction aids in the industrial preparation of alkanes. The method is used to prepare symmetrical alkanes, it is not used for asymmetrical alkanes. The reaction involves the exchange of halogen and metal with the involvement of radical species R to form a carbon-carbon bond arising in a nucleophilic substitution reaction. Wurtz reaction is one of the first name reactions in organic chemistry. It is a method to synthesize higher alkanes by a reaction between alkyl halides and metallic sodium in the presence of dry ether.

For example: