Problem 89 - A Complete Resource Book in Chemistry for JEE Main

Question

Which one of the following reactions is not associated with the Solvay process of manufacture of sodium carbonate? (a) \(\mathrm{NaCl}+\mathrm{NH}_{4} \mathrm{CO}_{3} \longrightarrow \mathrm{NaHCO}_{3}+\mathrm{NH}_{4} \mathrm{Cl}\) (b) \(2 \mathrm{NaOH}+\mathrm{CO}_{2} \longrightarrow \mathrm{Na}_{2} \mathrm{CO}_{3}+\mathrm{H}_{2} \mathrm{O}\) (c) \(2 \mathrm{NaHCO}_{3} \longrightarrow \mathrm{Na}_{2} \mathrm{CO}_{3}+\mathrm{H}_{2} \mathrm{O}+\mathrm{CO}_{2}\) (d) \(\mathrm{NH}_{3}+\mathrm{H}_{2} \mathrm{CO}_{3} \longrightarrow \mathrm{NH}_{4} \mathrm{HCO}_{3}\)

Step-by-Step Solution

Answer

The reaction not associated with the Solvay process is (b).

Step 1: Understanding the Solvay Process

The Solvay process is an industrial method used to produce sodium carbonate (\(\text{Na}_2\text{CO}_3\)) from sodium chloride (\(\text{NaCl}\)) and limestone (\(\text{CaCO}_3\)). Key steps involve the creation of ammonium bicarbonate (\(\text{NH}_4\text{HCO}_3\)) and intermediate reactions producing sodium bicarbonate (\(\text{NaHCO}_3\)).

Step 2: Analyzing Each Reaction

Evaluate each option to determine its relevance to the Solvay process:- **(a)** \(\text{NaCl} + \text{NH}_4\text{CO}_3 \to \text{NaHCO}_3 + \text{NH}_4\text{Cl}\)- **(b)** \(2 \text{NaOH} + \text{CO}_2 \to \text{Na}_2\text{CO}_3 + \text{H}_2\text{O}\)- **(c)** \(2 \text{NaHCO}_3 \to \text{Na}_2\text{CO}_3 + \text{H}_2\text{O} + \text{CO}_2\)- **(d)** \(\text{NH}_3 + \text{H}_2\text{CO}_3 \to \text{NH}_4\text{HCO}_3\)

Step 3: Matching Reactions to the Solvay Process

- **Reaction (a)**: Formation of sodium bicarbonate from sodium chloride is part of the Solvay process. - **Reaction (b)**: Direct conversion of sodium hydroxide to sodium carbonate is not part of the Solvay process. - **Reaction (c)**: Decomposition of sodium bicarbonate to sodium carbonate is part of the Solvay process. - **Reaction (d)**: Formation of ammonium bicarbonate is part of the Solvay process.

Step 4: Identifying the Odd Reaction

Reaction (b) does not align with the typical steps of the Solvay process. It involves sodium hydroxide, which is not used in the Solvay process to convert to sodium carbonate.

Key Concepts

Sodium Carbonate Production

The production of sodium carbonate, also known as soda ash, is a significant industrial process. One of the most prominent methods for producing sodium carbonate is the Solvay process. This involves several chemical reactions.
The Solvay process primarily utilizes sodium chloride (common salt) and limestone to produce sodium carbonate. A key intermediate in this process is the formation of sodium bicarbonate (\(\text{NaHCO}_3\)), which then decomposes into sodium carbonate.

• Sodium carbonate is widely used in the glass manufacturing industry.
• It plays a crucial role in detergents and soaps.
• Additionally, it's utilized in the production of paper.

Each of these uses highlights the necessity of efficient production methods like the Solvay process.

Industrial Chemistry Methods

Industrial chemistry entails the application of chemical processes for large-scale production. The Solvay process exemplifies one of these methods by integrating various reactions to achieve the desired product, sodium carbonate.
The Solvay process is a testament to how chemistry and engineering can work together. This method efficiently recycles ammonia, making it economically advantageous. It relies on the reaction between ammonia, carbon dioxide, and saltwater to create key intermediate compounds.

• It includes multiple stages like creating ammonia gas and filtrating crude sodium bicarbonate.
• Furthermore, by-products such as calcium chloride are also produced and utilized.
• The core principle is to ensure minimal waste and reusability of materials like ammonia.

This method highlights the innovation and complexities involved in industrial chemistry.

Chemical Reactions in Industry

Chemical reactions in industrial settings involve transformations that are optimized for efficiency and scalability. In the Solvay process, a series of reactions are carefully coordinated to produce sodium carbonate.
Key reactions in this process include the reaction between sodium chloride and ammonia to produce ammonium bicarbonate and sodium bicarbonate. Each step is designed to utilize and recycle reactants efficiently.

• For instance, carbon dioxide reacts with the ammonia solution to create ammonium bicarbonate, which is crucial for precipitating sodium bicarbonate from a brine solution.
• Additionally, a thermal decomposition of sodium bicarbonate yields sodium carbonate, completing the cycle.
• This meticulous orchestration of reactions ensures that the desired product is obtained with minimal resource wastage and environmental impact.

This highlights the importance of each reaction and its role within the industrial manufacturing process.