Caustic Soda Preparation Properties and Uses - Check Here

What is caustic soda?

Sodium hydroxide, also called as caustic soda or lye, is an inorganic chemical having the caustic soda formula NaOH. It's a white solid ionic compound made up of sodium cations Na⁺ and hydroxide anions OH^-. NaOH chemical name is caustic soda and sodium hydroxide chemical formula is NaOH.

It has a very caustic base and alkali which decomposes proteins at normal room temperature and cause chemical burns. It is highly soluble in water and easily absorbs carbon dioxide and moisture from the air. It produces a series of NaOH.nH₂O hydrates. Caustic soda chemical name is sodium hydroxide

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Caustic Soda Preparation

The following three processes can be used to make sodium hydroxide or Caustic soda:

1. Castner-Kellner process

2. Nelson Diaphragm cell

3. Loewig's process

Castner - Kellner Process

Principle

Electrolysis of brine solution is used in the Castner-Kellner procedure to obtain sodium hydroxide.

Castner-Kellner cell

It's a rectangular steel tank with ebonite lining on the interior. The titanium serves as an anode, while a mercury layer at the tank's bottom serves as a cathode.

The reaction that causes the ionization of brine solution is as follows:

2NaCl → 2Na⁺ + 2Cl^-

Ionization occurs when the brine solution comes into touch with an electric current. Both positive and negative ions travel towards the electrodes as a result. By generating a sodium amalgam, the sodium ions are deposited at the mercury cathode. Chlorine ions, on the other hand, travel towards the anode and exit the cell from the top.

At anode, the reaction is as follows:

2Cl^- → Cl2 + 2e^-

At cathode, the reaction is as follows:

2Na⁺ + 2e^- → 2Na

Nelson Diaphragm Cell

Principle

An aqueous NaCl solution is used as the electrolyte in this process (also called Brine).

Procedure

The metal oxide or asbestos porous diaphragm with the polymer divides the cathode and anode chambers. The diaphragm keeps hydroxide ions out of the anode compartment while keeping chloride ions out of the cathode compartment. The saturated brine reaches the anode compartment, resulting in the production of chlorine gas.

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Positive electrode

Ru-Ti oxide is used to coat carbon (also known as graphite) or titanium.

Cathode /Negative electrode- Steel Mesh

Reaction at Anode / Oxidation

2Cl^- (aq) → Cl2 (g) + 2e^-

Cathode Reaction / Reduction

2H₂O (l) + 2e^- → H₂ (g) + 2OH^- (aq)

By mixing with OH^- to create NaOH, Na⁺ migrates through the diaphragm to the cathode compartment.

Overall Cell Reaction (Showing Na⁺ Ions)

2H₂O (l) + 2Cl^- (aq) + 2Na⁺ (aq) → 2Na⁺ (aq) + 2OH^- (aq) + H₂ (g) + Cl₂ (g)

The NaOH(s) can be crystallized out of this product, which contains sodium hydroxide and sodium chloride.

Loewig's Process

The Loewig technique is used for making caustic soda and is based on the creation of sodium ferrate (Na₂FeO₄), which is then decomposed with water. The soda liquors are then combined with ferric oxide, and the mixture is evaporated to dryness before being calcined at a bright red temperature, usually in a revolving furnace. Calcination causes a reaction between iron oxide and sodium carbonate, resulting in the release of carbon dioxide and the retention of sodium ferrate in the furnace.

The bulk is rinsed in cold water until all soluble stuff has been removed, and then 900°C water is poured over the sodium ferrate. It decomposes, producing caustic soda and regenerating iron oxide. The last is returned to the calcining process. The ferric oxide utilized is natural iron ore that is free of silica and other impurities; ferric hydroxide that has been precipitated is not well suited to the process since it produces a product that is difficult to lixiviate.

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Properties of Caustic Soda

1. It's a white solid with a melting point of 591K.

2. It's a long-lasting substance.

3. NaOH is bitter and soapy to the touch.

4. It has a high-water solubility and a moderate solubility in alcohol.

5. Sodium hydroxide is an alkaline substance.

Caustic Soda Uses:

Aluminum, paper, industrial drain and oven cleaners, and detergents and soaps are all made with sodium hydroxide formula NaOH (also known as caustic soda).

Cleaning and disinfectant products containing sodium hydroxide

Soaps and other detergents that we use in our homes and businesses are made from sodium hydroxide, sometimes known as caustic soda. Sodium hydroxide and chlorine are combined to make chlorine bleach. Drain cleaners using caustic soda breakdown the fats and grease that can clog pipes into soap.

Caustic Soda Applications

Caustic soda is utilized in a variety of industries, including paper and pulp production, drinking water, textiles, detergents and soaps, and drain cleaning. As of 2004, the global production of caustic soda was around 60 million tonnes, whereas the consumption was around 51 million tonnes. Sodium Hydroxide is the chemical term for caustic soda, and its chemical formula is NaOH. Sodium hydroxide common name is caustic soda and chemical formula of caustic soda is NaOH.

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