A synthetic detergent is the sodium salt of sulphonic acid which has cleansing properties in water.
Structure Of Molecule Of Detergent
The structure of a synthetic detergent is similar to that of soaps. It consists of a long hydrocarbon chain which is hydrophobic and a short ionic part which is hydrophilic. The cleansing action of detergent is considered to be more effective than soap in hard water because a detergent does not give precipitate with salts of calcium and magnesium present in hard water.
Cleansing Action of Detergents
When detergents are dissolved in water, its hydrocarbon part attaches itself to grease and oil particles whereas its ionic part remains attached to water. Therefore, when dirty clothes are agitated in solution of detergents then dirt particles sticks to the hydrocarbon part of detergents and at the same time the water loving ionic part pulls away this dirt from clothes.
Advantages of Synthetic Detergents over Soaps
Synthetic detergents have following advantages over soaps:
- Synthetic detergents can be used even in hard water, while soaps cannot be used in hard water.
- Synthetic detergents are prepared from petroleum. So, the use of synthetic detergents helps us to save vegetable oils.
- These have a stronger cleansing action than soaps.
- These are more soluble in water than soaps.
Disadvantages of Synthetic Detergents
The main disadvantage of synthetic detergents is that some detergents are not biodegradable and hence cause water pollution in lakes and rivers after accumulating there.
How synthetic detergents cause water pollution?
Synthetic detergents are non-biodegradable. So, these remain in water bodies for a long time and make water unfit for drinking by aquatic animals. Synthetic detergents also cause rapid growth of algae in water bodies like rivers and lakes which leads to reduction of oxygen in water bodies. Due to reduction of oxygen in water the aquatic animals feel suffocation and can die.
Test your understanding and answer these questions:
- How synthetic detergents cause water pollution?
- Explain cleansing action of detergents.
- What are advantages of using detergents over soaps?
- What are disadvantages of using detergents?