Match the entries of column I with appropriate entries of column II and choose the correct option out of the four options given.

(a)-(iv), (b)-(iii), (c)-(ii), (d)-(i)

The correct answer is option 3. (a)-(iv), (b)-(iii), (c)-(ii), (d)-(i).

Let us go through each compound in detail to understand why they match the way they do:

(a) C₂H₅NH₂(iv) Ethyl amine:

Ethylamine, also known as ethanamine or monoethylamine, is an organic compound with the formula \(C_2H_5NH_2\).  It is a primary amine with the structure \(CH_3CH_2NH_2\).Ethylamine is a colorless, flammable gas at room temperature, but it can be condensed into a liquid by cooling or applying pressure. It has a strong, ammonia-like odor. Highly soluble in water and also soluble in alcohol, ether, and many organic solvents. Ethylamine is a weak base and can react with acids to form ethylammonium salts. It can undergo typical amine reactions, such as alkylation, acylation, and nitrosation. It can also participate in nucleophilic substitution and addition reactions.

Used in the production of pharmaceuticals, agricultural chemicals, rubber chemicals, and surfactants. Occasionally used as a solvent in organic synthesis. Used to make other chemicals such as ethyl isocyanate and ethylcarbamate. Ethylamine plays a significant role in various industrial processes due to its chemical properties and reactivity. However, its handling must be done with caution due to its toxicity and flammability.

(b) C₆H₁₀NH₂(iii) Cyclohexylamine:

Cyclohexylamine, with the chemical formula \(C_6H_{11}NH_2\), is an organic compound that is a primary amine derived from cyclohexane. Cyclohexylamine is a colorless to yellowish liquid at room temperature. It has a strong, fishy, ammonia-like odor. Miscible with water and soluble in most organic solvents, such as alcohol, ether, and benzene.

Cyclohexylamine is a weak base, similar to other amines, and can form salts when reacted with acids. It undergoes typical amine reactions, including alkylation, acylation, and reactions with nitrous acid to form diazonium salts. It can also engage in nucleophilic substitution reactions.

Used in the manufacture of a variety of chemicals, including rubber chemicals, corrosion inhibitors, and pharmaceuticals. Used as a corrosion inhibitor in boiler water treatment. Used to synthesize herbicides, insecticides, and other agrochemicals.

Cyclohexylamine is an important industrial chemical with numerous applications, particularly in the synthesis of other compounds and water treatment. However, careful handling and storage are crucial due to its toxic and flammable nature.

(c) C₆H₅NH₂(ii) Aniline:

Aniline, with the chemical formula \(C_6H_5NH_2\), is an organic compound that belongs to the class of aromatic amines. It consists of a phenyl group attached to an amino group. Aniline is a colorless to slightly yellow oily liquid at room temperature. It has a characteristic amine-like odor, somewhat reminiscent of rotten fish. Moderately soluble in water and highly soluble in most organic solvents such as ethanol, ether, and benzene.

Aniline is a weak base. Its basicity is less than that of aliphatic amines due to the electron-withdrawing effect of the phenyl ring, which decreases the availability of the lone pair on the nitrogen for protonation. Aniline undergoes several types of reactions: Reacts with acyl chlorides and alkyl halides to form amides and alkylated amines. Direct nitration of aniline is difficult due to its tendency to oxidize, but it can be achieved by protecting the amino group, can be sulfonated to form sulfanilic acid. Easily oxidized to form various compounds, including azobenzene and aniline black.

Aniline is a precursor to a wide variety of dyes, particularly indigo dye and other synthetic dyes. Used in the synthesis of numerous drugs and pharmaceuticals. Serves as an antioxidant and vulcanization accelerator in rubber processing. Acts as an intermediate in the production of various chemicals, including herbicides, fungicides, and explosives.

Aniline is a crucial industrial chemical with significant applications in dye manufacture, pharmaceuticals, and rubber processing. However, due to its toxicity and potential health hazards, careful handling and storage are essential to ensure safety.

(d) C₅H₁₀NH(i) Piperidine: 

Piperidine, with the chemical formula \(C_5H_{10}NH\), is an organic compound that belongs to the class of saturated heterocyclic amines. It consists of a six-membered ring containing five methylene groups and one nitrogen atom. Piperidine is a colorless to pale yellow liquid at room temperature. It has a distinctive, pungent, pepper-like odor. Miscible with water and soluble in most organic solvents, such as ethanol, ether, and chloroform.

Piperidine is a relatively strong base compared to many other amines, with a pKa around 11.12 for its conjugate acid.

Reactivity:

Nucleophilic Substitution: Can participate in nucleophilic substitution reactions due to the lone pair of electrons on the nitrogen.

Acylation and Alkylation: Can react with acyl chlorides and alkyl halides to form amides and alkylated amines.

Reductive Amination: Can be used in reductive amination reactions to form secondary and tertiary amines.

Used in the manufacture of pharmaceuticals, agrochemicals, and other organic compounds. Sometimes used as a solvent in organic synthesis. Acts as a base and catalyst in various chemical reactions, including the synthesis of polymers and pharmaceuticals.

Piperidine is an important industrial chemical with various applications in the synthesis of pharmaceuticals, agrochemicals, and other organic compounds. Its strong basicity and reactivity make it a valuable reagent in organic chemistry. However, due to its toxicity and flammability, careful handling and storage are essential to ensure safety.