Question

\(\mathrm{Cl}_{2}\) reacts with \(\mathrm{CS}_{2}\) in presence of \(\mathrm{I}_{2}\) to form (a) \(\mathrm{CCl}_{4}\) (b) \(\mathrm{Cl}_{3} \mathrm{C}-\mathrm{NO}_{2}\) (c) \(\mathrm{CHCl}_{3}\) (d) \(\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{Cl}\)

Short answer

The product formed is \( \mathrm{CCl}_{4} \).

Step-by-step solution

Understanding the Reactants

Identify the given reactants in the problem. Here, you have chlorine (\( \mathrm{Cl}_{2} \) ) and carbon disulfide (\( \mathrm{CS}_{2} \) ) reacting in the presence of iodine (\( \mathrm{I}_{2} \) ). This suggests a substitution reaction where chlorine will react with carbon disulfide.

Predicting the Reaction

Consider the typical reactions of \( \mathrm{CS}_{2} \) with halogens. \( \mathrm{CS}_{2} \) can react with \( \mathrm{Cl}_{2} \) in the presence of a catalyst like \( \mathrm{I}_{2} \) to undergo substitution, leading to the replacement of sulfur atoms and formation of chlorinated carbon compounds.

Analyzing Possible Products

Review each of the given potential products:(a) \( \mathrm{CCl}_{4} \) is formed by the complete substitution of the sulfur atoms with chlorine, which matches the behavior of the reactants.(b) \( \mathrm{Cl}_{3} \mathrm{C}-\mathrm{NO}_{2} \) is not related to the given reactants or typical outcomes.(c) \( \mathrm{CHCl}_{3} \) or chloroform does not fit as it involves hydrogen.(d) \( \mathrm{C}_2 \mathrm{H}_5 \mathrm{Cl} \) (ethyl chloride) involves an alkyl group not present in the reactants.

Finalizing the Correct Product

Given the nature of the reactants and typical reactions, the most plausible product is \( \mathrm{CCl}_{4} \), where sulfur is replaced by chlorine, forming carbon tetrachloride. The presence of \( \mathrm{I}_{2} \) facilitates the reaction but does not affect the final product choice.

Key concepts

Substitution Reaction

A substitution reaction is a fundamental concept in organic chemistry. It involves replacing one atom or group of atoms in a molecule with another atom or group. This type of reaction can reshape the molecular structure and properties. The chemical equation for substitution reactions typically follows the form:

• Reactant complex (A-B) + Substituting species (C) → Product complex (A-C) + Leaving species (B)

In the original problem, chlorine (\( \mathrm{Cl}_{2} \) ) replaces the sulfur atoms in carbon disulfide (\( \mathrm{CS}_{2} \) ). The result is the formation of carbon tetrachloride (\( \mathrm{CCl}_{4} \) ) where iodine serves as a catalyst.
A substitution reaction often involves one atom or group being more reactive. Therefore, it replaces another within the reactant compound. In our example, chlorine is more reactive than sulfur, leading to a successful substitution.

Halogenation

Halogenation refers to the process where one or more halogens (like fluorine, chlorine, bromine, or iodine) are introduced into a compound. With carbon disulfide (\( \mathrm{CS}_{2} \) ), halogenation happens when the chlorine atoms replace sulfur atoms, forming carbon tetrachloride (\( \mathrm{CCl}_{4} \) ).
In this mechanism, \( \mathrm{I}_{2} \) acts as a catalyst to promote the halogenation. Chlorine (\( \mathrm{Cl}_{2} \) ) molecules engage with sulfur, displacing them and forming a new bond with carbon.
This process illustrates how halogenation can significantly change chemical properties. It swaps out less electronegative elements, like sulfur, with highly reactive halogens, enhancing reactivity or altering physical characteristics.

Reaction Mechanism

Understanding reaction mechanisms is key to mastering organic chemistry. A reaction mechanism details each step of a chemical reaction, explaining how reactants transform into products.
In the case of chlorine reacting with carbon disulfide, the mechanism starts with the attack of chlorine on the sulfur atoms, supported by the presence of iodine. The electron-rich sulfur repels iodine activation, making it easier for chlorine to step in and form a bond with carbon, ultimately creating carbon tetrachloride. This understanding aids chemists in predicting and controlling chemical reactions.
By breaking down what's happening at each stage of the reaction, students can better grasp why certain products, like \( \mathrm{CCl}_{4} \) , form. A reaction mechanism provides a window into the energetic and electronic shifts at play.

Organic Chemistry

Organic chemistry is the study of carbon-containing compounds, exploring a vast array of chemical reactions and mechanisms. It includes understanding how and why carbon reacts with other elements, like chlorine in our example.
Within this field, reactions such as substitution and halogenation display the versatility and complexity of organic compounds. Organic chemistry requires a grasp of how molecular and electronic configurations shift during reactions.
Reactions like \( \mathrm{CS}_{2} \) undergoing halogenation with \( \mathrm{Cl}_{2} \) highlight the transformative power of chemical processes. Whether for creating materials or understanding biological interactions, organic chemistry underpins many real-world applications.
From pharmaceuticals to plastics, this branch of chemistry unlocks numerous possibilities by manipulating carbon bonds.