Hydroxide Definition

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In chemistry, hydroxide is a highly common name used for the diatomic anion OH, with hydroxide chemical formula OH−. Hydroxide consist of atoms of hydrogen and oxygen, generally extracted from the dissociation of a base. Hydroxide is an oxygen hydride that plays the role of a mouse metabolite. Hydroxide also makes for a conjugate base of water. It is one of the simplest diatomic ions known to any chemical reaction. Hydroxide ion is a type of ligand which actively donates a pair of electrons, conducting as a Lewis base. Examples include the aurate ion [Au (OH)4] and - the aluminate ion [Al (OH)4].

Hydroxide Chemical Formula Reaction

The hydroxide ion develops salts, few of which dissociate in aqueous solution, freeing up the solvated hydroxide ions. A hydroxide linked to a strongly electropositive centre may ionize itself, freeing up a hydrogen cation (H+), forming the parent compound which is an acid.

Sodium Hydroxide Formula

One of the most common inorganic bases or alkalis, sodium hydroxide, is also called caustic soda or Lye. The chemical formula of sodium hydroxide is NaOH with a molar mass of 40.01 g/mol.

Sodium Hydroxide Structure

Sodium hydroxide (NaOH) is an ionic compound composed of a sodium cation (Na+) and hydroxide (OH-) anion. It is the alkali salt of sodium of which the chemical structure is shown below:

NaOH(s) → Na+(aq) + OH-(aq)

Sodium Hydroxide Preparation

Sodium hydroxide is industrially produced by undergoing the process of electrolytic chloralkali. In the process, electrolysis of the aqueous sodium chloride solution provides chlorine gas and sodium hydroxide. Sodium hydroxide is acquired as a solution in water with a composition of 50% and is then dried to make solid sodium hydroxide pellets or flakes. Below is the chemical chain that occurs in the preparation of NaOH.

2 NaCl + 2 H2O → 2 NaOH + Cl2 + H2

Sodium Hydroxide Physical & Chemical Properties

Physical Properties: The main physical property of NaOH is that it is white crystalline solid which is odourless having a density of 2.13 g/mL and the melting point of 318 °C. Because of this physical property of NaOH, it is widely available as granules, pellets and flakes and also as aqueous solutions of different concentrations.

Chemical Properties: Sodium hydroxide is highly soluble in polar solvents such as water, ethanol and methanol. It is insoluble in organic solvents such as alcohols, esters, ethers and benzene or acetone. Dissolving solid NaOH in water will result in a highly exothermic reaction and the consequent aq. NaOH solution will be a colourless, odourless and crucial base used in the laboratory. Having a strong base, sodium hydroxide instantly reacts with acids such as HCl, to create the corresponding salts, as mentioned below:

NaOH + HCl → NaCl + H2O

Sodium hydroxide is highly hygroscopic meaning that it readily absorbs water from the air as well as carbon dioxide from the atmospheric air.

Uses of Sodium Hydroxide

Sodium hydroxide is one of the most widely used chemical bases in industrial applications. The extensive use of NaOH is mainly in industries such as textiles industry, paper and pulp industry, petroleum industry, etc. It is used in the manufacturing of soaps and detergents and for cleaning drinking water and drain cleaner. Also known as lye and caustic soda, it is also widely used in the Bayer process of aluminium production, industrial disinfecting and pH regulation. NaOH is also used in the food industry for various applications.

NaOH has its own set of benefits as protection against many health/safety hazards. It is a highly powerful and corrosive alkali, which easily decomposes living organism tissues.

Health Hazards Associated With Sodium Hydroxide

Skin contact with NaOH solutions can lead to severe chemical burns and eye contact can cause permanent blindness. Solid NaOH produces a high exothermic reaction (corrosive) when it reacts with water and acids and thus can cause burns by splashing.

Fun Facts

  • NaOH is a multi-million-ton annual commodity chemical.

  • The worldwide production of sodium hydroxide was approximately 60 million tonnes in 2004 while 42 million tonnes was produced in 2005 using the Solvay process.

  • The principal method used to manufacture NaOH is the chloralkali process.

  • Solutions consisting of the hydroxide ion are formed when a salt of a weak acid is solvated in water.

  • Sodium carbonate is used as an alkali, for example, through the hydrolysis reaction.

FAQ (Frequently Asked Questions)

Q1. What is the Use of Sodium Carbonate in Daily Life?

Ans: Though the base strength of the concentrated sodium hydroxide solution is higher than the sodium carbonate solutions, the latter has the benefit of being solid. An example of the application of sodium carbonate as an alkali is washing soda (another name for sodium carbonate) acts on insoluble esters, such as triglycerides, carboxylic acid, etc. it hydrolyzes them and makes them soluble.

Q2. Which is the Hydroxide of Aluminium? Mention its Use.

Ans: Bauxite, a standard hydroxide of aluminium, is the primary ore from which the metal is produced. In the same manner, lepidocrocite (γ-FeO (OH)), goethite (α-FeO (OH)) and elementary hydroxides of iron are among the primary ores used for the manufacturing of metallic iron. Various other uses can be found on individual hydroxides.

Q3. Is it Possible for Hydroxide to Exist on its Own?

Ans: Hydroxide can exist alone when it is in water since bases and acids can act upon to neutralize each other in the solution. However, it is quite crucial in such an event to distinguish between HO and H2O in reactions.

Q4. Is there Any Reason Why Hydroxide is Written as OH?

Ans: Hydroxide is written in "reverse order" because hydroxide is a polyatomic ion that still requires to be balanced to be part of a compound. When OH attaches with another ion, the oxygen is the one that attaches to the other ion. This is the reason why it is written as OH, so it will be easier to tell how the molecule is bonded.