Problem 49 - A Complete Resource Book in Chemistry for JEE Main

Question

Chloroform when reacts with nitric acid, gives (a) \(\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{C}(\mathrm{NO})_{5} \mathrm{SH}\) (b) \(\mathrm{CCl}_{3} \mathrm{CHOH}\) (c) \(\mathrm{CCl}_{3} \mathrm{NO}_{2}\) (d) \(\mathrm{CCl}_{3} \mathrm{NO}_{3}\)

Step-by-Step Solution

Answer

(c) \( \mathrm{CCl}_{3} \mathrm{NO}_{2} \)

Step 1: Understanding Reactants

Identify the reactants in the given chemical reaction: chloroform (\( \mathrm{CHCl}_3 \)) and nitric acid (\( \mathrm{HNO}_3 \)). Understanding that these reactants will undergo a chemical reaction to form an organic nitro compound is crucial.

Step 2: Reaction Type

Recognize that nitric acid can act as a nitrating agent, introducing nitro groups (\( \mathrm{NO}_2 \)) into organic compounds. In this context, we are looking for an organic product of chloroform and \( \mathrm{HNO}_3 \).

Step 3: Expected Product Analysis

Consider the possible products that can be formed from \( \mathrm{CHCl}_3 \) and \( \mathrm{HNO}_3 \). Since nitric acid is a nitrating agent, a likely product is an organic compound containing \( \mathrm{NO}_2 \) group.

Step 4: Match with Options

Examine the given options to find the compound that has the general structure expected from the nitration of \( \mathrm{CHCl}_3 \). Check if one of the options contains a \( \mathrm{NO}_2 \) group attached to the \( \mathrm{CCl}_3 \) group.

Step 5: Solution Identification

Compare each available option: - (a) \( \mathrm{C}_{2} \mathrm{H}_{5} \mathrm{C} (\mathrm{NO})_{5} \mathrm{SH} \) does not correlate with expected nitration.- (b) \( \mathrm{CCl}_{3} \mathrm{CHOH} \) lacks a nitro group.- (c) \( \mathrm{CCl}_{3} \mathrm{NO}_{2} \), includes \( \mathrm{NO}_{2} \) group, likely correct.- (d) \( \mathrm{CCl}_{3} \mathrm{NO}_{3} \) possesses more complex structure than simple nitration expects.

Key Concepts

Chemical Reaction Types

Chemical reactions are processes where reactants are transformed into different substances, known as products. These reactions can be classified into several types based on how reactants interact and what products are formed.

• Combination Reactions: Two or more substances combine to form a single product.
• Decomposition Reactions: A single compound breaks down into two or more substances.
• Displacement Reactions: An atom or ion in a compound is replaced by an atom or ion of another element.
• Combustion Reactions: A substance combines with oxygen, releasing energy in the form of light and heat.
• Redox Reactions: Involve the transfer of electrons between two substances.

In the case of chloroform reacting with nitric acid, this is a type of substitution reaction. Here, the nitro group (\( \mathrm{NO}_2 \)) from nitric acid substitutes a hydrogen atom in the chloroform molecule. This can specifically be classified as a nitration reaction, where an organic compound undergoes a change due to the introduction of a nitro group.

Nitro Compounds

Nitro compounds are a type of organic molecule that contain one or more nitro functional groups (\( -\mathrm{NO}_2 \)). These compounds are significant in both industrial and laboratory settings.

• They play a crucial role in the manufacturing of explosives, pharmaceuticals, and dyes.
• The nitro group is highly polar, generally increasing the solubility of compounds in polar solvents.
• They are typically synthesized through nitration reactions, where a nitro group is introduced into a compound.
• These compounds are also valuable intermediates in organic synthesis, often serving as precursors to amines via reduction processes.

In the reaction between chloroform and nitric acid, the formation of a nitro compound, such as\( \mathrm{CCl}_{3} \mathrm{NO}_{2} \), is observed. This results from the nitration process, where nitric acid introduces the nitro group into the chloroform molecule.

Chloroform

Chloroform (\( \mathrm{CHCl}_3 \)) is an organic compound that is part of the trihalomethane group. It is a colorless, sweet-smelling liquid that is denser than water. Here are some key attributes and uses of chloroform:

• It was historically used as an anesthetic in medical procedures due to its sedative properties.
• Nowadays, it is primarily used as a solvent in the laboratory and industrial settings.
• Chloroform is also a precursor for the production of other compounds, including refrigerants like R-22.
• Due to its volatility and effects on human health, prolonged exposure must be strictly controlled.

In the context of the reaction with nitric acid, chloroform serves as the substrate undergoing nitration, where one of its hydrogen atoms is replaced by a nitro group to form a new compound.

Nitrating Agents

Nitrating agents like nitric acid (\( \mathrm{HNO}_3 \)) are crucial in adding nitro groups (\( \mathrm{NO}_2 \)) to organic compounds, a process known as nitration. This is a vital method in chemistry for introducing such functional groups into carbon structures.

• Nitric acid is one of the most common nitrating agents due to its ability to donate nitro groups to organic molecules.
• The process usually requires highly controlled conditions because nitration reactions can be vigorous and exothermic.
• During the nitration reaction, nitric acid can form nitronium ion (\( \mathrm{NO}_2^+ \)), which is the actual species responsible for the nitration process.
• Nitrating agents are extensively used in the synthesis of nitro compounds, which are important precursors in the creation of dyes, explosives, and pharmaceuticals.

In the chemical reaction between chloroform and nitric acid, the nitric acid acts as a nitrating agent. It introduces the nitro group to the chloroform, resulting in the formation of nitroform (\( \mathrm{CCl}_{3} \mathrm{NO}_{2} \)).