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Difference Between Soap and Detergent - Properties and FAQs

Difference Between Soap and Detergent - Properties and FAQs

Edited By Team Careers360 | Updated on Jul 02, 2025 04:52 PM IST

Soaps are sodium or potassium salt of carboxylic acid attached to a long aliphatic chain. While detergents are sodium or potassium salt of benzene sulphonic acid generally alkyl benzene sulphonates. Soap and detergent are used for the removal of dirt, impurity, and grease. Soap when coming in contact with water and impurity forms lather and remove dirt while detergents covert the insoluble substance into its soluble form. Let us now discuss soap first. Soaps are also given the name surfactant and because it reduces the surface tension between liquids.

This Story also Contains
  1. Properties of Soap
  2. Types of Soaps
  3. Toilet Soaps
  4. Non-Toilet Soap
  5. Glycerine Soap
  6. Transparent Soap
  7. Liquid Soap
  8. Kitchen Soap
  9. Washing Soap
  10. Novelty Soap
  11. Medicated Soap
  12. Beauty Soap
  13. Grad 1 Soap
  14. Detergent Soap
  15. Preparation of Soap
  16. Characteristic Property of Detergents
  17. How is Detergent Made?

Saponification of fats and oils is the general method for the preparation of soaps that is from plant and animal fats. The carboxylate end of the soap molecule is hydrophilic in nature and the hydrocarbon tail is hydrophobic which means they are amphiphilic. It is also the metal salt of a fatty acid that can be used for lubrication and cleaning purposes. If the solution contains minerals that will significantly increase the effect of soap, solutions containing minerals are chosen prior to solutions that do not contain minerals.

They are biodegradable so when talking about the environment, soaps are good. And also it is produced from natural ingredients. Soaps do not work well in hard water because hard water contains calcium and magnesium ions which when contact with the hard water developed by the solder it is called scum.

Image of soap

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When talking about detergent they are usually surfactant and having cleaning properties when they are formed as a dilute solution with water. Just like a soap it also contains a hydrophobic and hydrophilic region that is there are also amphiphilic in nature. Detergents are sodium salt of phosphates or sulfate. In compared to soap detergents works well in hard water as it does not form any scum with calcium and magnesium ions present in hard water. And it is a very important property of detergent that is easily soluble in hard water as well.

Also has a very good cleaning action than soaps do. Detergents are prepared with the help of phosphates dioxide and surfactants to salt and citric acid. Detergents in the dry solid form are most commonly used but also detergents in the liquid form are also now present which is prepared with the use of a high amount of water during the preparation procedure.

Image of detergent powder

detergent powder

Properties of Soap

Some of the important properties of soap are described below;

  • The sodium or potassium salt of the carboxylic acid is defined as soap and is attached to a long aliphatic chain.

  • Soaps are given the name surfactant due to their ability to reduce the surface tension between the liquid and some other substance and also it is very good for the emulsification process of oils in water.

  • They are produced by a process called saponification with the help of fats and oils that are generally natural in origin.

  • They are amphiphilic in nature having a hydrophilic and hydrophobic group in a single molecule of soap.

  • Soap is a type of salt.

  • Soaps are generally used for washing, bathing, and as a cleaning agent in household activities.

  • In addition to the domestic application, it also finds some industrial application that it can be used as a lubricant and also a catalyst precursor.

  • The action of soap in cleaning is to form lather when rinsed with water and it kills microorganisms present in the dirt.

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Types of Soaps

Soaps are categorized depending on their usage and production method some of these soaps are described below.

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Toilet Soaps

The soaps that have a high efficiency to clean East toilet soaps because the TFM that is total fatty matter in comparison to other soap is very high. They have cosmetic use as well.

Non-Toilet Soap

The stop that can clean heavy dirty like grease and stains are known toilet soaps. They are also called hard soap. This type of soap is used for lubrication actions just like greases.

Glycerine Soap

As glycerine is a component of fat and oil glycerine is formed as a byproduct in the chemical reaction for the making of soap. But many manufacturers purposefully remove this glycerine for making that for some other cosmetic products preparation.

Transparent Soap

The soap that is made by the hot process method is transparent in nature that during their preparation some form of alcohol is added to make it transparent. As a substitute for alcohol sugar syrup is also used for making a transparent sore but alcohol is more good. A ready-made soap base is now available in the market for transparent soap preparation.

Liquid Soap

In comparison to soap bars, the making process of liquid soap is much more complicated than it, requires a hot process method also. Hindi preparation process potassium hydroxide is used instead of sodium hydroxide and it makes the soap in the liquid form and more water is added during the procedure.

Kitchen Soap

The soap mainly used for dishwashing is kitchen soap. They are not safe for the skin.

Washing Soap

Mainly used for washing clothes as it removes dirt and grease from the clothes. When dirt and grease come in contact with this it forms lather and removes dirt along with water. It is also used as a lubricant and thickeners in the industrial field.

Novelty Soap

The soaps that are found in various shapes colors like fish, cake, etc. are novelty soap. Mainly prepared for enjoyment and entertainment for children who use them.

Medicated Soap

Soaps that contain antiseptics and disinfectants for killing bacteria medicated soap.

Beauty Soap

The soap containing ingredients for a different type of skin and different flavors of fragrance are beauty soap. It contains glycerine.

Grad 1 Soap

The quality of soap is determined by the value of TFM. The soaps having 76 percent TFM minimum are grad 1 soap.

Detergent Soap

Any substance that is used for cleaning purposes is detergent. So soap is a type of detergent that is mild in its cleaning action. Soaps are made up of fatty acids from natural ingredients and it contains oils and fat. While detergents are made by artificial derivatives.

Preparation of Soap

The carboxylic acid with long-chain alkyl group is fatty acids. When this fatty acid is heated in presence of sodium hydroxide or potassium hydroxide solution soaps are formed since the process involved in the formation of soap is called saponification. It is a hydrolysis reaction. Soaps are obtained the first in the form of a colloidal form which is then precipitated by adding sodium chloride. For the making of antibacterial soap compounds such as triclocarban and triclosan are also added.

Characteristic Property of Detergents

  • Detergents are chemical substances that are commonly used for removing grease and stains and soaps are a type of detergent.

  • One of the important ingredients in detergents is surface-active agents.

  • They are very good dinner hard water as it does not form scum with hard water.

  • Detergents are water-soluble and they make impurities and grease in a form of a soluble substance and which can be then removed easily by using water.

  • Detergent is not made from natural means so it is not biodegradable also.

Also read -

How is Detergent Made?

Detergents are not made by the saponification process and it requires a huge chemical processor so they are generally prepared in a chemical plant.

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Frequently Asked Questions (FAQs)

1. What is detergent?

Detergents are a type of chemical substance used for washing clothes and dishes present in the form of powder or liquid. They are generally sulphonate or ammonium salt of long-chain carboxylic acids.

2. What is the use of common salt in the soap industry?

Common salt is one of the important ingredients used in the manufacture of soap. During the manufacture of soap first, a colloidal solution is obtained common salt is used to precipitate out soap as it reduces the solubility of soap in water. The process is called salting out in chemistry.

3. Give detergent meaning.

A water-soluble cleaning agent activates the formation of water-soluble substances from impurities and grease. And are easy works on hard water without forming scum.

4. Give soap meaning.

A water-soluble cleaning agent and a type of detergent used for the removal of impurity and grease by converting them into a lather and thereby removing impurity by the action of water.

5. Give two properties of soap.

The sodium or potassium salt of the carboxylic acid is defined as soap and is attached to a long aliphatic chain.

Soap is a type of salt.

6. Why do detergents work better in hard water compared to soaps?
Detergents work better in hard water because they don't react with the calcium and magnesium ions present in hard water. Soaps, on the other hand, form insoluble precipitates (soap scum) with these ions, reducing their cleaning effectiveness. Detergents maintain their cleaning power regardless of water hardness.
7. How do soaps and detergents clean at the molecular level?
Both soaps and detergents are surfactants, meaning they have a hydrophilic (water-loving) head and a hydrophobic (water-repelling) tail. The hydrophobic tail attaches to oil and grease, while the hydrophilic head remains in water. This allows the dirt to be suspended in water and washed away.
8. How does the pH of soaps differ from that of detergents?
Soaps are generally alkaline with a pH between 9-10, while detergents can be formulated to have a wider pH range, from slightly acidic to alkaline. This pH flexibility allows detergents to be tailored for specific cleaning tasks or to be pH-neutral for sensitive surfaces.
9. Can soaps and detergents be used interchangeably?
While both clean, they are not always interchangeable. Detergents are often more versatile and can be used in a wider range of conditions, including cold water and hard water. Soaps may be preferred for gentle cleaning of skin and certain fabrics but may not be as effective in all situations.
10. What role does the critical micelle concentration (CMC) play in soap and detergent effectiveness?
The critical micelle concentration (CMC) is the concentration at which surfactant molecules begin to form micelles. At or above the CMC, soaps and detergents are most effective at removing dirt and oil. Detergents typically have a lower CMC than soaps, making them effective at lower concentrations.
11. How do soaps and detergents affect surface tension of water?
Both soaps and detergents lower the surface tension of water. This reduction in surface tension allows water to spread out and penetrate fabrics or surfaces more easily, enhancing the cleaning process. Detergents generally lower surface tension more effectively than soaps.
12. How do soaps and detergents differ in their ability to form calcium and magnesium salts?
Soaps readily form insoluble calcium and magnesium salts (soap scum) in hard water, which reduces their cleaning effectiveness. Detergents, particularly those containing builders, either do not form these insoluble salts or form more soluble complexes with calcium and magnesium ions, maintaining their cleaning power in hard water.
13. How do soaps and detergents interact differently with cell membranes?
Soaps, being more alkaline, can be harsher on cell membranes and may cause more irritation to skin and eyes. Detergents can be formulated to be milder and less disruptive to cell membranes. This is why many personal care products use mild detergents (such as sodium lauryl sulfate) rather than traditional soaps.
14. Why are detergents often preferred in cold water washing?
Detergents are preferred in cold water washing because they remain effective at lower temperatures. Soaps tend to solidify and become less soluble in cold water, reducing their cleaning power. Detergents maintain their surfactant properties across a wider temperature range, making them more versatile for various washing conditions.
15. How do soaps and detergents differ in their ability to form emulsions?
Both soaps and detergents can form emulsions, but detergents are generally more effective emulsifiers. This is because detergents have a wider range of molecular structures that can be tailored for specific emulsification needs, allowing them to stabilize oil-water mixtures more effectively in various conditions.
16. What is the main difference between soap and detergent?
The main difference lies in their chemical composition. Soaps are made from natural ingredients like animal fats or vegetable oils, while detergents are synthetic compounds derived from petroleum products. This difference affects their properties and performance in various water conditions.
17. Why are enzymes often added to detergents but not to soaps?
Enzymes are added to detergents to break down specific types of stains, such as proteins or starches. They are not typically added to soaps because the alkaline nature of soap can denature (inactivate) the enzymes. Detergents can be formulated to provide a stable environment for enzymes to function effectively.
18. What is the "salting out" effect in soap production, and why doesn't it apply to detergents?
"Salting out" is a process used in soap production where salt is added to separate the soap from the solution. This works because soap molecules are less soluble in salty water. Detergents don't undergo this process because they are synthesized differently and remain soluble even in the presence of salts.
19. How do the biodegradability of soaps and detergents compare?
Soaps are generally more biodegradable than traditional detergents because they are made from natural fats and oils. However, many modern detergents are now formulated to be biodegradable. The rate of biodegradation can vary depending on the specific chemical structure of the surfactants used in each product.
20. Are soaps more environmentally friendly than detergents?
Generally, soaps are considered more environmentally friendly because they are biodegradable and made from renewable resources. However, some modern detergents are also designed to be biodegradable. The environmental impact depends on the specific formulation and manufacturing process of each product.
21. How do the antimicrobial properties of soaps compare to those of detergents?
While both can have antimicrobial properties, especially when specific additives are included, soaps generally have inherent mild antimicrobial properties due to their alkaline nature. Detergents can be more easily formulated with a wide range of antimicrobial agents to suit different needs, from mild to strong disinfectant properties.
22. What is the difference between the saponification process for soaps and the synthesis of detergents?
Saponification, used to make soap, is a reaction between fats/oils and a strong base (like sodium hydroxide). It's a relatively simple process that yields soap and glycerin. Detergent synthesis, on the other hand, involves more complex chemical processes, often starting with petroleum-based compounds. This allows for greater control over the final product's properties.
23. What is the role of builders in detergents, and why aren't they typically used in soaps?
Builders in detergents serve to soften water by binding to calcium and magnesium ions, enhance cleaning performance, and maintain alkalinity. They're not typically used in soaps because soaps are less effective in hard water regardless of builders, and the natural soap-making process doesn't allow for easy incorporation of these additives.
24. Why are some detergents better at removing protein-based stains than soaps?
Some detergents are better at removing protein-based stains because they can be formulated with enzymes like proteases, which break down proteins. Additionally, the pH of detergents can be optimized for protein removal. Soaps, being consistently alkaline, may not provide the ideal conditions for breaking down protein stains.
25. How do soaps and detergents differ in their ability to remove pesticide residues?
Detergents are often more effective at removing pesticide residues than soaps. This is because many pesticides are oil-based, and detergents can be formulated with stronger oil-dissolving properties. Additionally, some detergents include specific additives designed to break down or bind to pesticide molecules, enhancing their removal.
26. What is the difference between the way soaps and detergents interact with grease and oil at the molecular level?
Both soaps and detergents have hydrophobic tails that interact with grease and oil. However, detergents can be designed with more varied and sometimes more effective hydrophobic portions. This allows them to penetrate and dissolve oily substances more efficiently. Additionally, detergents maintain this ability in various water conditions, while soap's effectiveness can be compromised in hard water.
27. How do the foaming properties of soaps and detergents differ?
Soaps generally produce more foam than detergents, especially in soft water. However, the amount of foam doesn't necessarily indicate cleaning power. Detergents can be formulated to produce varying amounts of foam, and some are specifically designed to be low-foaming for use in machines like dishwashers.
28. What is the significance of the hydrophilic-lipophilic balance (HLB) in soaps and detergents?
The hydrophilic-lipophilic balance (HLB) is a measure of the relative strength of the hydrophilic and lipophilic portions of a surfactant molecule. It determines the molecule's affinity for oil and water phases. Detergents can be formulated with a wide range of HLB values for specific applications, while soaps have a more limited HLB range.
29. How do the molecular structures of soaps and detergents influence their cleaning mechanisms?
The molecular structures of both soaps and detergents include a hydrophilic head and a hydrophobic tail. However, detergents can have more varied structures, including branched chains and different ionic groups. This structural diversity allows detergents to be tailored for specific cleaning tasks and conditions, often resulting in more effective and versatile cleaning action.
30. How do soaps and detergents differ in their ability to form micelles?
Both soaps and detergents form micelles, but detergents typically form micelles at lower concentrations (lower critical micelle concentration). Detergent micelles are often more stable across a range of conditions (pH, temperature, water hardness) compared to soap micelles. This contributes to the greater effectiveness of detergents in various cleaning situations.
31. How do soaps and detergents differ in their performance at different water temperatures?
Soaps perform best in warm to hot water, as heat helps melt the soap and increase its solubility. Detergents, especially those formulated for cold water, can perform well across a wider temperature range. This is because detergents maintain their surfactant properties and solubility even at lower temperatures.
32. Why do some people prefer soap for personal hygiene?
Some people prefer soap for personal hygiene because it's often gentler on the skin and can be made from natural ingredients. Soaps may also be less likely to strip away natural oils from the skin. However, this preference can vary based on individual skin types and needs.
33. How do the sudsing properties of soaps and detergents affect their cleaning efficiency?
While soaps generally produce more suds, the amount of suds doesn't necessarily correlate with cleaning efficiency. Detergents can be formulated to produce varying levels of suds while maintaining cleaning power. In fact, many high-efficiency detergents are low-sudsing but highly effective. The key to cleaning is the surfactant action, not the visible foam.
34. How do soaps and detergents differ in their impact on wastewater treatment processes?
Soaps, being biodegradable, generally have less impact on wastewater treatment processes. However, in hard water areas, they can contribute to the buildup of lime soap deposits in pipes. Some detergents, especially older formulations, can be more challenging for wastewater treatment plants to process, potentially affecting aquatic ecosystems. Modern biodegradable detergents aim to minimize these impacts.
35. How do soaps and detergents differ in their ability to clean synthetic fabrics?
Detergents are generally more effective at cleaning synthetic fabrics than soaps. Synthetic fibers often have oil-loving (oleophilic) properties, which can make them prone to oily stains. Detergents, with their tailored surfactant structures, can penetrate these fibers more effectively and remove oily soils. Soaps may leave residues on synthetic fabrics, especially in hard water.
36. Why are some detergents better at maintaining fabric colors than soaps?
Some detergents are formulated with color-protecting agents that help prevent dye transfer and color fading. These agents can work by either forming a protective layer on fabric fibers or by deactivating elements in the water that might cause color fading. Traditional soaps lack these specialized additives and may be harsher
37. Why are some detergents better suited for automatic washing machines than soaps?
Detergents are better suited for automatic washing machines because they produce less foam (which can interfere with machine operation), work effectively in hard water, and can include enzymes and other additives that enhance cleaning in a machine environment. Soaps can leave residues, produce excessive foam, and are less effective in the hard water conditions often encountered in machine washing.
38. How do soaps and detergents differ in their impact on fabric fibers?
Soaps, especially in hard water, can leave residues on fabric fibers that make clothes feel stiff. Detergents, particularly those with fabric softeners, are less likely to leave residues and can help maintain fabric softness. Some detergents are also formulated to protect fiber integrity better than traditional soaps.
39. How do soaps and detergents differ in their ability to remove different types of stains?
Detergents generally outperform soaps in stain removal, especially for oily and protein-based stains. This is due to their more diverse molecular structures and the ability to include specific stain-targeting additives. Soaps are more limited in their stain-removing capabilities, particularly in hard water or on synthetic fabrics.
40. Why are some detergents better at preventing soil redeposition during washing than soaps?
Detergents are often better at preventing soil redeposition because they can include specific anti-redeposition agents in their formulation. These agents help keep the removed soil suspended in the wash water, preventing it from settling back onto the cleaned surface. Soaps lack these additives and may allow some redeposition, especially in hard water conditions.
41. Why are detergents often more effective at removing oily stains than soaps?
Detergents are often more effective at removing oily stains because they can be tailored to have stronger oil-dissolving properties. Their synthetic nature allows for more precise control over the hydrophobic portion of the molecule, which interacts with oils. Additionally, detergents perform better in various water conditions, maintaining their effectiveness.
42. What is the difference between anionic and non-ionic detergents, and how does this compare to soap?
Anionic detergents have a negatively charged hydrophilic end, while non-ionic detergents have no charge. Soaps are always anionic. This difference affects how they interact with different types of dirt and surfaces. Non-ionic detergents, for example, are often better at removing oily soils and work well in cold water, while anionic detergents (including soaps) are generally better at removing particulate soils.
43. Why are detergents often preferred in industrial and commercial cleaning applications?
Detergents are preferred in industrial and commercial cleaning because of their versatility and effectiveness in various conditions. They can be formulated for specific tasks, work well in hard water, function effectively at different temperatures, and can include additives like enzymes and builders. Soaps are more limited in their formulation options and performance range.
44. How do soaps and detergents differ in their ability to clean in saltwater?
Detergents generally perform better than soaps in saltwater. The high concentration of ions in saltwater can cause soap molecules to precipitate, reducing their cleaning effectiveness. Many detergents, especially those designed for marine use, can maintain their surfactant properties and cleaning ability even in high-salinity environments.
45. What is the difference between the rinsing properties of soaps and detergents?
Detergents typically rinse away more easily than soaps, especially in hard water. Soap can leave a film or residue (soap scum) that's difficult to rinse off, particularly on fabrics and surfaces. Detergents, being more soluble in various water conditions, tend to rinse away more completely, leaving less residue.
46. Why are some detergents more effective at removing mineral deposits than soaps?
Some detergents are more effective at removing mineral deposits because they can be formulated with specific chelating agents or sequestrants. These additives bind to mineral ions, preventing them from redepositing on surfaces. Soaps, lacking these additives, may actually contribute to mineral buildup, especially in hard water areas.
47. What is the difference between the emulsifying properties of soaps and detergents?
While both soaps and detergents can emulsify oils in water, detergents generally have superior emulsifying properties. This is because detergents can be designed with a wider range of hydrophilic-lipophilic balance (HLB) values, allowing them to stabilize emulsions more effectively in various conditions. Soaps have a more limited range of emulsifying capabilities.

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