Question

In solvay process of manufacture of \(\mathrm{Na}_{2} \mathrm{CO}_{3}\), the by products are: (a) \(\mathrm{CaCl}_{2}, \mathrm{CO}_{2}, \mathrm{NH}_{3}\) (b) \(\mathrm{Na}_{2} \mathrm{CO}_{3}, \mathrm{CO}_{2}\) (c) \(\mathrm{NH}_{4} \mathrm{Cl}, \mathrm{CaO}\) (d) \(\mathrm{CaO}, \mathrm{Na}_{2} \mathrm{CO}_{3}\)

Short answer

The by-products are \(\text{CaCl}_2\), \(\text{CO}_2\), and \(\text{NH}_3\) (option a).

Step-by-step solution

Understanding the Solvay Process

The Solvay process is an industrial method for producing sodium carbonate (\(\text{Na}_2\text{CO}_3\)). It primarily uses common salt (\(\text{NaCl}\)), limestone (\(\text{CaCO}_3\)), and ammonia (\(\text{NH}_3\)) as raw materials.

Identifying Reactions in the Solvay Process

In the Solvay process, carbon dioxide (\(\text{CO}_2\)) and ammonia (\(\text{NH}_3\)) are used to convert sodium chloride (\(\text{NaCl}\)) to sodium bicarbonate (\(\text{NaHCO}_3\)), which is then heated to form sodium carbonate (\(\text{Na}_2\text{CO}_3\)). Calcium chloride (\(\text{CaCl}_2\)) is a major by-product formed in this process.

Listing By-products of the Solvay Process

The major by-product of the Solvay process is calcium chloride (\(\text{CaCl}_2\)). Other substances like \(\text{CO}_2\) and \(\text{NH}_3\) are involved in the process, but they are not by-products. The by-products are those substances that remain when the reaction is completed and are not part of the desired product.

Selecting the Correct Option

By reviewing the options, the correct by-products are those not desired in the production of the main product, sodium carbonate. Here, option (a) lists calcium chloride as one of the by-products, which aligns correctly with the known by-products of this process.

Key concepts

Sodium Carbonate Production

The Solvay Process is a widely used industrial method for producing sodium carbonate, also known as washing soda. This process begins with common salt, also known by its chemical name as sodium chloride (\( \text{NaCl} \)). Together with another naturally occurring mineral, limestone (\( \text{CaCO}_3 \)), and ammonia (\( \text{NH}_3 \)), these materials serve as the starting ingredients in the manufacturing of sodium carbonate.
The key reaction steps involve the conversion of sodium chloride into sodium bicarbonate (\( \text{NaHCO}_3 \)). This occurs through the use of carbon dioxide (\( \text{CO}_2 \)) and ammonia. This sodium bicarbonate is then heated to produce sodium carbonate. This final heating step is crucial as it breaks down sodium bicarbonate to release carbon dioxide and water, forming the desired sodium carbonate.

• The Solvay process conserves ammonia within the system, minimizing waste and reducing costs.
• This cyclical nature makes the process efficient and economically favorable compared to other methods.

Sodium carbonate is a valuable chemical in the making of glass, paper, soap, and detergents, proving its importance in industrial chemistry.

By-products of Chemical Reactions

In industrial processes like the Solvay Process, by-products are often generated. These are substances formed in parallel to the main desired product, in this case, sodium carbonate. One of the primary by-products of the Solvay Process is calcium chloride (\( \text{CaCl}_2 \)). This compound emerges from the reaction of carbon dioxide and ammonia with calcium oxide (\( \text{CaO} \)), within the overall process.
While calcium chloride is the main by-product, it's interesting to note that substances like \( \text{CO}_2 \) and \( \text{NH}_3 \) are not waste products. They are essential reactants within the cycle, continually reused within each turn of the process to ensure minimal waste.

• By-products like calcium chloride can be used elsewhere, such as in de-icing roads or as a drying agent.
• Efficiently managing by-products is pivotal in minimizing environmental impacts.

Industrial Chemistry

Industrial chemistry involves the large-scale synthesis of chemicals essential to our daily lives. A prime example is the Solvay Process for sodium carbonate production. It exemplifies how intricate chemical processes are orchestrated on a massive scale to produce necessary compounds efficiently.
The role of industrial chemistry in society cannot be overstated:

• It provides the foundation for the manufacture of everyday products like glass, detergents, and textiles.
• Industrial chemistry focuses on optimizing the efficiency of chemical reactions, cutting costs, and reducing environmental impacts.

The Solvay Process also exemplifies a cyclic chemical process, emphasizing the importance of recycling reactants to minimize waste and improve environmental sustainability. Such advancements illustrate the potential of industrial chemistry to harmonize production needs with ecological concerns. This balance remains a crucial goal in today's manufacturing industries.