Chemistry plays a vital role in everyday life. It has impacted our lives so much that we do not even acknowledge that we encounter chemicals every moment. The washing soda we use to clean our clothes is sodium carbonate. Moreover, acidity reliever ENO contains magnesium hydroxide in it.
Soda Ash
Soda ash, commonly known as washing soda used for cleaning clothes, is a sodium carbonate molecule with the molecular formula of Na2CO3. When dissolved in water, it is a colourless and odourless compound that yields sodium hydroxide and carbonic acid. It is also referred to as the diazonium salt of carbonic acid.
Sodium carbonate is a neutral molecule with one carbon atom, two sodium atoms, and three oxygen atoms. In soda ash, sodium cation carries a +1 charge, while the carbonate anion has a -2 charge. Its structure is given below.
Preparation of soda ash
We can use the Solvay, Leblanc, Dual, and Electrolytic processes to prepare soda ash. In the Solvay process, ammonia and carbon dioxide are passed in the saturated sodium chloride solution at low temperatures, forming a sodium hydrogen carbonate precipitate.
2NH3 + H2O + CO2 → (NH4)2CO3
(NH4)2CO3 + H2O + CO2 → 2NH4HCO3
NH4HCO3 + NaCl → NH4Cl + NaHCO3
Sodium hydrogen carbonate precipitate can be separated by filtration and can be ignited to form sodium carbonate.
2NaHCO3 → Na2CO3 + CO2 + H2O
Properties of soda ash
| Soda Ash | |
| Common Name | Washing Soda |
| Chemical Formula | Na2CO3 |
| Structure | |
| Molecular Mass | 105.9888 g/mol |
| Melting Point | 851 °C |
| Boiling Point | 1,600 °C |
| Density | 2.54 g/cm³ |
Applications of soda ash
There are a lot of applications of soda ash. A few of them are mentioned below.
- It is used as a cleansing agent for washing clothes.
- It is an essential component of dry soap powder.
- It removes sulphur dioxide and hydrochloric acid from stack gases.
- It functions as a glass flux or silicate flux.
- It acts as a sodium hydroxide substitute in the pulp and paper industry.
- It is used to clean air and soften the hard water.
Milk of Magnesia
Milk of magnesia is the common name for magnesium hydroxide molecules. It occurs in the form of the mineral brucite. Milk of magnesia is used to balance stomach acid and relieve indigestion or heartburn. It is slightly soluble in water and essential to laxatives and antacids.
Magnesium hydroxide is a neutral molecule with one magnesium atom, two hydrogen, and two oxygen atoms. Its structure is given below. Magnesium cation carries a +2 charge, while the hydroxide anion has a -1 charge.
Preparation of milk of magnesia
We can prepare milk of magnesia by combining any magnesium salt with alkaline water.
Mg2+ + 2OH− → Mg(OH)2
Magnesium salts are commonly found in seawater. Thus, we can readily extract it from seawater by alkalinisation.
Properties of milk of magnesia
| Milk of Magnesia | |
| Chemical Name | Magnesium Hydroxide |
| Chemical Formula | Mg(OH)2 |
| Structure | |
| Molecular Mass | 58.3197 g/mol |
| Melting Point | 350 °C |
| Boiling Point | It decomposes on heating. |
| Density | 2.3446 g/cm3 |
Applications of milk of magnesia
There are a lot of applications of milk of magnesia. A few of them are mentioned below.
- It is used as an antacid to neutralise excess stomach acid.
- It is used to relieve indigestion or heartburn.
- It is used as a fire retardant.
- It is used as a laxative to relieve constipation.
- It is used in cleaning wastewater.
- It is used as a food additive and in gold mining.
