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Sodium (Na) is a chemical element in the periodic table’s alkali metal group (Group 1 [Ia]). Sodium is a silvery-white metal that is extremely soft. Sodium is the most abundant element on Earth and the most common alkali metal, accounting for 2.8 percent of the Earth’s crust. It is abundant in nature in the form of compounds. Sodium is extremely reactive, forming a wide range of compounds with almost all inorganic and organic anions (negatively charged ions). It has an oxidation state of +1 normally, and its single valence electron is easily lost, yielding the colourless sodium cation (Na+). Components containing sodium anion, Na, have also been developed. The four most common sodium compounds are chloride, carbonate, hydroxide, and sulphate. Sodium hydroxide (Na OH) is a caustic metallic base that is also known as lye or caustic soda.
The information about sodium hydroxide from various chemistry-related articles is available here. Sodium hydroxide (NaOH) is a caustic metallic base that is also known as lye or caustic soda, and it plays a vital role in chemistry. Students who want to flourish in chemistry need to be well known about sodium hydroxide to get deep knowledge about it to do well on their exams. The definition, preparation, properties, and uses are provided here to assist students in effectively understanding the respective topic.
Overview
Caustic soda( Sodium Hydroxide), an alkali, is widely used in many industries, primarily as a strong chemical base in the production of pulp and paper, textiles, drinking water, and detergents. In 1998, global production was estimated to be around 45 million tonnes. Sodium hydroxide is also the most commonly used base in chemical laboratories, as it can test for a wide range of cations (this is known as Qualitative Inorganic Analysis) and provide alkaline mediums for some reactions that require it such as the Biuret test.
Pure sodium hydroxide is a white solid that comes in pellets, flakes, granules, and a 50% saturated solution. It should be stored in an airtight container because it is deliquescent and readily absorbs carbon dioxide from the air. It is very soluble in water and releases a lot of heat. It also dissolves in ethanol and methanol, though its solubility in these solvents is lower than that of potassium hydroxide. In ether and other non-polar solvents, it is insoluble.
Sodium Hydroxide
In general, sodium hydroxide (NaOH) is a corrosive white crystalline solid that readily absorbs moisture and dissolves when exposed to it. Sodium hydroxide, also known as caustic soda or lye, is the most commonly used industrial alkali. It is extremely corrosive to both animal and plant tissue. When dissolved in water, it forms alkaline solutions that neutralise acids in a variety of commercial processes: in petroleum refining, it removes sulfuric and organic acids; in soapmaking, it reacts with fatty acids. NaOH solutions are used in the treatment of cellulose and the production of many chemicals.
Preparation and Properties Sodium Hydroxide
Sodium hydroxide is being prepared by:
(1) Castner-Kellner process:
In general, the Castner-Kellner method involves the electrolysis of brine solution to produce sodium hydroxide.
Mercury cathode cell or Castner Kellner cell: One such cell is made up of a rectangular iron tank in which mercury flows along the bottom and serves as the cathode. The brine solution flows in the same direction as the anode, which is composed of a number of graphite blocks. When an electric current flows through a cell, the following reactions occur at both electrodes:
NaCl→Na++Cl–
Anode: 2Cl–→Cl2+2e–
Cathode: Na++e–→Na
Na+HgNaHg (sodium amalgam)
Because the cathode in this cell is mercury, the sodium atoms produced dissolve in mercury and form an amalgam, and it escapes and reacts with water to produce sodium hydroxide and hydrogen gas.
2NaHg+2H2O→2NaOH+2Hg+H2
The pure mercury is returned to the electrolysis tank.
(2) Nelson Diaphragm cell:
In this, an aqueous NaCl solution is used as the electrolyte in this process (also called Brine).
The cathode and anode compartments are separated by a porous diaphragm made of metal oxide or asbestos and polymer. The diaphragm keeps hydroxide ions out of the anode compartment and chloride ions out of the cathode compartment. As a result of the saturated brine entering the anode compartment, chlorine gas is produced.
2NaCl(aq)+2H2O(l)→2NaOH(aq)+H2(g)+Cl2(g)
(3) Loewig’s Process:
Loewig’s method for producing caustic soda is based on the formation of sodium ferrate, which is then decomposed with water. Following that, the soda liquors are combined with ferric oxide, and the mass is evaporated to dryness and calcined at a bright red heat, typically in a revolving furnace. Calcination causes a reaction between iron oxide and sodium carbonate, resulting in the escape of carbon dioxide and the retention of sodium ferrate in the furnace.
The quantity is washed with cold water until all soluble matter is removed, and then 900 °C water is poured over the sodium ferrate. It breaks down, releasing caustic soda and replenishing iron oxide. The last is brought back to the calcining process. The ferric oxide used is natural iron ore that is free of silica and other impurities; ferric hydroxide, which is made by calcining precipitated ferric hydroxide, is not well suited to the process because it produces a product that is difficult to lixiviate.
Properties of Sodium Hydroxide:
- This is a white solid with a melting point of 591 degrees Celsius.
- It really is a stable substance.
- NaOH is bitter and has a soapy taste.
- It is very soluble in water and only slightly soluble in alcohol.
- Sodium hydroxide is a highly alkaline substance.
Sodium Hydroxide in Water
NaOH is the chemical formula for sodium hydroxide. The element sodium is an alkali metal, and the –OH group is known as hydroxide. Because sodium hydroxide produces the hydroxide ion, it is a base.
Ionic compounds include sodium hydroxide. It is known that the ionic compound dissociates into ions in water. When the base sodium hydroxide dissolves in water, it splits into sodium ions and chloride ions.
NaOH→Na+(aq)+OH-(aq)
Because sodium hydroxide is a colourless solid, its ions do not impart any colour to the solution when dissolved in water.
As a result, the sodium hydroxide in water produces a colourless solution.
Use of Sodium Hydroxide
- It’s being used as a cleaning agent as well as in the production of washing soda.
- In laboratories, sodium hydroxide is sometimes used as a reagent.
- Often used in the manufacture of soda lime.
- It can be used in the purification of bauxite in the extraction of aluminium.
Also read: Mechanism of Electrophilic Addition
FAQs
What is the role of caustic soda in the industrial cleaning process?
Because caustic soda dissolves grease, protein-based deposits, fats, and oil, it is mixed with water and heated before being used to clean process equipment and storage tanks.
How toxic is sodium hydroxide?
Sodium hydroxide has no systemic toxicity, but it is extremely CORROSIVE and can cause severe burns in all tissues with which it comes into contact. Sodium hydroxide is especially dangerous to the eyes because it can hydrolyze protein, causing severe eye damage.
What happens when you mix sodium hydroxide and water?
Because it is an exothermic reaction, sodium hydroxide explodes when it reacts with water. It's worth noting that when you pour NaOH into water drop by drop with constant shaking, heat is released, but in very small amounts because there's only a trace of acid in comparison to the water reacting with it.
