Problem 160 - A Complete Resource Book in Chemistry for JEE Main

Question

$$ \begin{aligned} &\text { Match the following }\\\ &\begin{array}{ll} \hline \text { Column-I } & \text { Column-II } \\ \hline \text { (a) Castner Kellner } & \text (p) \mathrm{MgCl}_{2} .5 \mathrm{MgO} \cdot \mathrm{xH}_{2} \mathrm{O} \\ \text { cell } & \text { (q) } \mathrm{K}_{2} \mathrm{CO}_{3} \\ \text { (b) Pearl ash } & \text { (r) Manufacture of } \mathrm{NaHCO}_{3} \\ \text { (c) Solvay's process } & \text { (s) Manufacture of } \mathrm{NaOH} \\\ \text { (d) Sorel's cement } & \text { (s) } \\ \hline \end{array} \end{aligned} $$

Step-by-Step Solution

Answer

(a)-(s), (b)-(q), (c)-(r), (d)-(p).

Step 1: Understanding Castner Kellner Cell

The Castner Kellner cell is used in electrochemical processes to produce sodium hydroxide (NaOH) from brine (saltwater) using electrolysis. Therefore, option (a) in Column-I corresponds to producing NaOH, making the match: (a) - (s).

Step 2: Identifying Pearl Ash

Pearl ash is another name for potassium carbonate (K2CO3). It is used as a drying agent and in glass production. Therefore, option (b) in Column-I relates to K2CO3 from Column-II, providing the match: (b) - (q).

Step 3: Understanding Solvay's Process

Solvay's process is an industrial method for the production of sodium bicarbonate (NaHCO3) or baking soda from sodium chloride and limestone. Therefore, option (c) in Column-I corresponds to producing NaHCO3, hence the match is: (c) - (r).

Step 4: Determining Sorel's Cement

Sorel's cement, also known as magnesium oxychloride cement, is formed by a reaction involving magnesium chloride and magnesium oxide. Therefore, option (d) in Column-I corresponds to the chemical composition given, matching it with MgCl2.5MgO.xH2O from Column-II: (d) - (p).

Key Concepts

Castner Kellner Cell

The Castner Kellner cell is a fascinating piece of electrochemical innovation. It is mainly used for producing sodium hydroxide (NaOH) through the process of electrolysis. Here, the starting material is brine, or saltwater, which contains sodium chloride (NaCl).
During electrolysis:

• The cell breaks down the brine solution.
• Chlorine gas is released at the anode.
• Hydrogen gas is released at the cathode.
• Sodium hydroxide remains in the solution.

Sodium hydroxide is an essential chemical used in many industries. It is vital for the production of soap, paper, and textiles. The efficient and effective design of the Castner Kellner cell allows for the large-scale production of NaOH, meeting the high demand in various sectors. Electrolysis that takes place in the Castner Kellner cell keeps the process clean and environmentally friendly, making it a preferred choice for industrial manufacturing.

Solvay Process

The Solvay process is a significant industrial method used for producing sodium bicarbonate (NaHCO3), commonly known as baking soda. The process relies on the reaction between sodium chloride (table salt) and limestone (calcium carbonate) with ammonia as a mediator.
Steps of the Solvay process include:

• Dissolving ammonia in a salt brine solution.
• Pumping carbon dioxide through the solution.
• Reacting components to form ammonium bicarbonate.
• Reacting further with salt brine to yield sodium bicarbonate.

The Solvay process is a remarkable example of chemical innovation. It was developed as a cost-effective method of producing baking soda on a large scale. Sodium bicarbonate is crucial in baking, cleaning, and various chemical processes. The method successfully balances economic and environmental considerations, making it a cornerstone in industrial chemistry.

Sorel's Cement

Sorel's cement, also known as magnesium oxychloride cement, is an interesting and unique construction material. It is formed by the reaction of magnesium chloride (MgCl2) with magnesium oxide (MgO). This mixture forms a strong and durable bond, making Sorel's cement suitable for diverse applications.
Advantages of Sorel's cement:

• High compressive strength.
• Fast setting, reducing construction time.
• Fire-resistant properties, enhancing safety.

Sorel's cement is utilized in flooring, fireproofing, and constructing various architectural elements. Due to its robustness and versatility, it is a preferred choice in modern construction. Its formation involves a chemical reaction that results in a solid matrix, ensuring high-performance standards in the applications it is used for.