Soap and Detergent

What is soap?
Soap is a salt that is formed from the reaction between an alkali and a fatty acid, RCOOH

-sodium palmitate
-sodium stearate
-sodium laurate
-sodium oleate

How is soap made?

Stage 1

  • The two parts of the oil or fat (ester) molecules are separated by heating the oil with alkaline solution through the hydrolysis process.
  • In this process, the oil or fat (ester) molecule is broken up into fatty acid and glycerol by water in the presence of alkali which acts as a catalyst.


Stage 2

  • The fatty acid that is released in Stage 1 reacts with alkali to form sodium salt fatty acid which is soap

What is detergent?

Is a salt that is produced from the reaction between an alkali and a sulphonic acid. Detergent is also the sodium salt of sulphonic acid. Examples:-

-sodium alkyl
 -sodium dodecyl sulphate ( sodium lauryl sulphate)

How is detergent made?

-This is a process diagram of detergent production.

-Sodium alkyl sulphate can be prepared through a neutralisation reaction between an alkyl sulphonic acid with a sodium hydroxide solution.

-The sodium dodecyl sulphate detergent is prepared through a neutralisation reaction between the dodecyl sulphonic acid and a sodium hydroxide solution.

How Does Soap and Detergent Work?

Generally, the soap ion structure can be represented as below

Soap molecules can reduce the surface tension of water to allow it to wet a material’s surface better.

• The soap molecule dissolves in water and reduces the surface tension of water. Water wets the dirty surface.
• The hydrophylic region dissolves in water.
• The hydrophobic region dissolves in dirt such as grease.
• The tail region emulsifies and breaks up the grease into small drops.

• When shaken, the water molecules will attract the soap ions and cause the grease to detach from the surface of the material.
• The soap bubbles to help float the grease emulsion in the water. When rinsed, the grease will be removed with the water.

How is soap and detergent different in hard water?

Hard water?
Hard water is the water that contains mineral salts, of which the majority of it are calcium and magnesium ions.

What are detergent additives for?

My Soap Survey…


Comments: Uses Potassium Laureate, and Streareth as its soap agent. Also uses orange peel oil Tetrasodium EDTA as fragrance. 


Comments:Uses Sodium Laureth Sulfate as its soap agent. 

3.Guardian, Syringa cream hand wash

Comments:Uses Sodium Laureth Sulfate as its soap agent. 

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