Hydroxide Ion

In chemistry, Hydroxide is the most common name for the diatomic anion, OH−. Hydroxide ions consist of hydrogen and oxygen. Hydroxide ion bonds are held together by a single covalent bond. This bond carries a negative charge and is one of the simplest polyatomic ions with a -1 charge. 

Hydroxide ions form different salts and some of the salts segregate in an aqueous solution. Hydroxide ions and hydroxides are relatively common in nature. Many useful chemicals and chemical processes have hydroxide ions and hydroxides – take, for example, potassium hydroxide used in agriculture and sodium hydroxide used in different industries as a strong base.

What are hydroxide ions?

It is a polyatomic ion with a negative OH charge consisting of hydrogen and oxygen. Hydroxide bases are a group of bases consisting of hydroxide ions. Some of the common hydroxide-ion compounds are ammonium hydroxide, potassium hydroxide, and sodium hydroxide. Bauxite and limonite are mineral ores that are examples of hydroxides. The formula of hydroxide ion is OH-.

Formation of hydroxide ions 

The hydration reaction of rare Earth metals and alkali metals is the most prevalent method of hydroxide formation. 

Let us look at the formation of sodium hydroxide. To get sodium hydroxide, add metallic sodium into water.

 2Na + 2H2O → 2NaOH + H2

To get a metal’s hydroxide that does not react directly with water, an exchange reaction or metathesis takes place. Here is an example:

CuSO4 + 2NaOH → Cu(OH)2 + Na2SO4

Hydroxide ions as a chemical base

Hydroxide ions are used in most compounds as chemical bases and are involved in neutralisation and numerous acid-base reactions. Arrhenius base is a substance that produces hydroxide ions when dissolved in an aqueous solution. An example of an Arrhenius base substance is NH3,  also known as ammonia: 

NH3(g) + H2O(I) ⇌ NH4(aq) + OH-(aq)

Base salts are salts that contain hydroxides that will dissociate into one or more hydroxide ions in water and cations that make the basic solution. These salts would undergo the process of neutralisation reaction with acids. 

An acid-alkali reaction can be simplified to:

OH-(aq) + H+(aq)  → H2O(I)

Use or applications of hydroxide ions 

There are various applications and uses of hydroxide ions. These are as follows:

1. Caustic soda or sodium hydroxide are used in industries as a strong base. Some of its uses include making drinking water, textiles, pulp and paper, detergent, and soaps.

2. It is also used as a drainage cleaner.

3. Iron hydroxide minerals such as limonite and goethite are used as low-grade brown iron ores. 

4. Potassium hydroxide is used in agriculture.

5. Aluminium hydroxides are used for making aluminium ore, bauxite. 

There are several common uses of hydroxides. They are:

1. They receive hydrogen ions or protons from acids for formation of water. The equation for this is:

 H+ + OH- → H2O

2. Hydroxyl radicals can also be found in other organic compounds such as sugars, soaps, and fats (lipids). 

3. They are also used to clean air by absorbing acidic gases like carbon dioxide and sulphur dioxide. 

4. A few hydroxides like slaked lime Ca(OH)2 can be used to prepare calcium carbonate (CaCO3) and ammonia.

Properties of hydroxide ions 

Structure of hydroxide ions 

Conclusion

In the above article, we have discussed the basic features of hydroxide ions, their uses, properties and so on. Hydroxide ions are polyatomic ions with a negative charge, consisting of hydrogen and oxygen. Its chemical formula is OH-. Hydroxyl radicals found in organic compounds such as sugars, soaps, and fats (lipids). Some of its uses include making drinking water, textiles, pulp and paper, detergent, and soaps.