Laundry Detergents And Stain Removal

Effects of Chemical Constituents of Laundry Detergents and Methods of Stain Removal Sarah M. Don

Chemistry EEI Semester 4, 2008 Dr Stolarchuk

September 17, 2008

Contents 1 Background 1.1 Types of Stains . . . . . 1.1.1 Organic Stains . 1.1.2 Inorganic Stains 1.1.3 Pigments . . . . 1.2 Stain Removal . . . . . 1.2.1 Water . . . . . . 1.2.2 Surfactants . . . 1.2.3 Phosphates . . . 1.2.4 Acids and Bases 1.2.5 Enzymes . . . . . 1.2.6 Oxidising Agents 1.2.7 Temperature . .

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2 Aim

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3 Procedure

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4 Results

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5 Product Evaluation 5.1 Sard Wonder Soap . 5.2 Baking Soda . . . . 5.3 OMO Liquid . . . . 5.4 Drive . . . . . . . . 5.5 Napisan Oxy-Action 5.6 Bleach . . . . . . . . 5.7 Lemon Juice . . . . . 5.8 Tap Water . . . . . . 5.9 Overall . . . . . . . .

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6 Conclusion A Stain Removal Solutions’ Effectiveness A.1 Aim . . . . . . . . . . . . . . . . . . . A.2 Equipment and Materials . . . . . . . A.3 Procedure . . . . . . . . . . . . . . . . A.4 Results . . . . . . . . . . . . . . . . . .

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Different Stains . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

B Determining the pH of the Stain Removal Solutions B.1 Aim . . . . . . . . . . . . . . . . . . . . . . . . . . . . B.2 Equipment and Materials . . . . . . . . . . . . . . . . B.3 Procedure . . . . . . . . . . . . . . . . . . . . . . . . . B.4 Results . . . . . . . . . . . . . . . . . . . . . . . . . . .

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C Conductivity of the Stain Removal Solutions C.1 Aim . . . . . . . . . . . . . . . . . . . . . . . C.2 Equipment and Materials . . . . . . . . . . . C.3 Procedure . . . . . . . . . . . . . . . . . . . . C.4 Results . . . . . . . . . . . . . . . . . . . . . .

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D Solubility of the Stain Removal Solutions D.1 Aim . . . . . . . . . . . . . . . . . . . . . D.2 Equipment and Materials . . . . . . . . . D.3 Procedure . . . . . . . . . . . . . . . . . . D.4 Results . . . . . . . . . . . . . . . . . . . .

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E Redox Indicator Test E.1 Aim . . . . . . . . . . . . E.2 Equipment and Materials E.3 Procedure . . . . . . . . . E.4 Results . . . . . . . . . . .

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2

1

Background

There are many different methods for the removal of stains. However, various types of stain removers work differently on varying stains. It is important to understand the science behind why different stain removal solutions work in order to know what kind of solvent to use on a certain kind of identifiable stain. A stain’s constituents’ molecular structure and composition determine how well and in what way the stain can be removed from the fabric.

1.1 1.1.1

Types of Stains Organic Stains

An organic molecule is one that is made up of a carbon chain with oxygen, hydrogen and other non-metals attached. Some of such compounds are polar while others are non-polar, depending on what functional groups are attached. Polymers, such as polysaccharides, are organic, and often need to be broken down into shorter chains (even monomers) before they can be dissolved.

1.1.2

Inorganic Stains

Inorganic compounds can usually be dissolved by inorganic solvents when a replacement or addition reaction occurs. The interaction between an inorganic, ionic solvent and solute can be altered by redox reactions. If the molecules of a stain are involved in a redox reaction, the composition of the stain changes into another compound so that it may become colourless and appear as though it has been washed out.

1.1.3

Pigments

Most pigments contain chromophores which are molecules that contain double bonds that absorb and emit a particular wavelength of light which defines the colour of the stain. Tannin, an organic compound, is a kind of pigment with a red-brown colour found in coffee and red wine. Tannin, however, is not very responsive to oxidation and basic solvents, thus making it difficult to remove from fabrics. The green colour of grass is provided by the pigment chlorophyll, also an organic chromophore.

1.2

Stain Removal

Different types of stain removal solutions interact differently with various types of stains. The polarity, size and solubility of the molecules in both the stain and the stain removal solution determine how well the stain can be lifted from the fabric. When considering what kind of solvent dissolves a particular substance, the idea that ‘like dissolves like’ can be adopted. Water (which is inorganic) dissolves inorganic compounds, while only organic solvents dissolve organic substances. To dissolve an organic compound in an inorganic solvent (and vice versa), a surfactant must be added to the solvent (see Section 1.2.2).

1.2.1

Water

Water is considered a universal solvent. Because of the bent water molecule’s polarity, it is able to dissolve other polar molecules as well as ionic compounds. As mentioned in Section 1.2, water is an inorganic solvent, so it can only dissolve inorganic substances. However, with the aid of surfactants (such as detergent), organic substances can also be suspended in an aqueous solution.

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1.2.2

Surfactants

Surfactants are molecules that have one polar end and one non-polar end, making them able to reduce the surface tension of a solvent or reduce the interfacial tension between two solutions. Micelles, such as phospholipids, have a hydrophobic (non-polar) and a hydrophilic (polar) end that allow it to form a layer between water-based and oil-based substances (see Figure 1).

Figure 1: Left - Micelle in water with hydrophilic head on the outside. Right - Micelle in oil-based solution with hydrophobic end facing outward. (Wikipedia, 2008) Surfactants can emulsify compounds that are not normally soluble in a particular medium. (Wikipedia, 2008) The micelles form a coating on the insoluble particles, and because the micelle itself is soluble because of the head group’s favourable interactions with the water, the previously insoluble compound can then be dissolved. (Donker, 1998)

1.2.3

Phosphates

Phosphates are ionic compounds that contain a phosphate group (PO4 −3 ). The part of blood that causes the rust-coloured stain to occur is iron oxide (Fe2 O3 ). Iron phosphate, however, is colourless, so solutions that contain phosphates are able to ‘remove’ blood stains because a displacement reaction occurs between the iron oxide and the phosphate compound. F e2 O3 + 2XP O4 → 2F eP O4 + X2 O3 The oxide group in Fe2 O3 is replaced with a phosphate group to make FePO4 , which is colourless. However, the actual mass of the biological material remains in the fabric unless surfactants are present to dissolve the organic material as well.

1.2.4

Acids and Bases

The concept of ‘like dissolves like’ can also be applied to acids and bases. Most soaps contain sodium hydroxide (NaOH) an alkali which is polar and therefore interacts favourably with water and can dissolve basic. Lemon juice contains citric acid, which is a reducing agent as well as an acid-solvent, so stains that are acid-based or oxidants can be easily suspended from the fabric. So if the approximate pH of a stain is known, a cleaning solution of similar pH can be effectively used to remove the stain.

1.2.5

Enzymes

Some laundry detergents contain enzymes. Certain molecules of the stain latch onto the active site of an enzyme as the substrate to form an enzyme/substrate complex, and the enzyme breaks the molecule into smaller sections that may be more easily dissolved (see Figure 2). Such enzymes suited to laundering usually

4

work best in warm water, and so instructions on laundry detergents’ packaging to use warm water is sometimes an indication that the detergent contains enzymes.

Figure 2: Enzyme breaking up stain molecule into smaller pieces On the other hand, sometimes laundry detergents incorrectly state on the packaging that they contain enzymes. Often, however, what they really mean is that the laundry detergent contains oxidising agents.

1.2.6

Oxidising Agents

Bleach, a solution of sodium hyperchlorate (NaOCl) and hydrogen peroxide (H2 O2 ), is a very strong oxidising agent. When bleach oxidises a chromophore, some of the energy released in the redox reaction is taken from the double bonds, leaving the chromophore with only single bonds. Because these single bonds don’t allow for the release of trapped energy in the form of photons at visible wavelengths, the pigment stain appears colourless. If only some of the double bonds are broken, however, the stain may only appear faded or as an entirely different colour. (Wikipedia, 2008) Oxidation reactions also release oxygen molecules. Because it is less dense than the liquid, the oxygen gas rises to the top of the solution, disturbing the molecules of the stain. By disturbing the stain molecules with oxygen, the parts of the stain may become dislodged from the fabric. So oxidising agents can be helpful in removing stains. (Wikipedia, 2008)

1.2.7

Temperature

Besides facilitating the function of enzymes, temperature has other effects on how well laundry detergents (or any other solvents) work. By increasing the temperature, the particles in both the stain and the solvent are given more energy, causing them to vibrate faster. This assists the solvent in dislocating the stain particles from the fibers of the fabric, and also makes it more difficult for the stain to reattach. Too much heat can sometimes cause certain types of stain to become ‘fixed’ or ‘set’ into the fibers of the fabric which makes the stain particles even harder to remove. However, cold water may not allow the chemical ingredients in the stain removal solution to do their job properly.

5

2

Aim

The objective of this investigation was to identify the effectiveness of certain laundry detergents and stain removal methods by comparing their constituents’ chemical properties.

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Procedure 1. Extensive background research was done on the constituents of stains and laundry detergents, as well as other stain removal methods. 2. The experiments in steps 5-9 were designed. 3. MSDS sheets of the hazardous chemicals required to conduct the experiments were obtained. (See Appendix F) 4. A journal containing research, notes, ideas, planning and the results of the experiments was maintained throughout the investigation. 5. A cleaning test was conducted to identify which stains could be removed by which stain removal solutions. (See Appendix A) 6. The pH of the stain removal solutions was identified. (See Appendix B) 7. The conductivity of the stain removal solutions was tested. (See Appendix C) 8. The solubility of the stain removal solutions in water, oil, acid and basic solvents. (See Appendix D) 9. The redox potential of the stain removal solutions was determined. (See Appendix E)

10. This research paper was written to explain the science behind the results of this extended experimental investigation.

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Results Table 1: Collaboration of the Results from all the Chemical Conducted on the Stain Removal Solutions Cleaning Solution pH Conductivity Solubility Redox Sard Wonder Soap 9 2 w*, o*, b Baking Soda 8 5 w, a, b Omo Liquid 7 1 w, a, b Drive 11 3 w, b Napisan Oxy-action 10 4 w, a, b Bleach 8 4 w, a, b Lemon Juice 4 4 w, o*, a, b* Tap Water 7 1 w, a, b

Tests Potential X × X X X X X ×

Solubility: w = water, o = oil, a = acid, b = base *partially dissolved

Sard Wonder Soap Baking Soda OMO Liquid Drive Napisan Oxy-Action Bleach Lemon Juice Tap Water

Table 2: Effectiveness of Stain Removal Solutions Coffee Beetroot Blood Grass Red Wine Foundation Ink None 4 5 4 4 4 3 2 5 2 4 4 2 3 0 0 5 4 4.5 4.5 4 4 1 2 5 3 4.5 4 3 3 2 1 5 4.5 5 4 4.5 4.5 1 0.5 5 5 5 5 5 5 0 0 4.5 3 3 2 2 2 0 0 4.5 3 3 3 1 3 0 0 5

Stain Removal Effectiveness: 0 = no change, 5 = no trace

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5

Product Evaluation

5.1

Sard Wonder Soap

Sard Wonder Soap is alkaline and contains surfactants, reducing agents and some ionic compounds. It is also soluble in basic solvent and partially soluble in water and oil. This suggests that the soap contains molecules with the properties of a base, fats (surfactants), polar and possibly ionic compounds. Most of the stains responded well1 to Sard Wonder Soap, except foundation and ink. However, foundation and ink responded better to Sard Wonder Soap than to any other cleaning solution. Most of the stains’ strength of colour was heavily reduced, however traces of the stains did remain. The mass of the stains was most likely removed by the surfactants and oxidising agents in the soap. Both organic and inorganic parts of the stain were able to be removed because of the polarity of the water in which the Sard Wonder Soap was dissolved, and the glycerol that the soap most likely contained.

5.2

Baking Soda

Baking soda is a basic salt, which is why it was such a good conductor and ineffective on all the stains other than beetroot and blood. The results from the experiments conducted in this investigation were not conclusive enough to determine how the beetroot stain was able to be mostly removed. However, the remaining yellowbrown traces of the beetroot stain were most likely due to some form of organic, non-polar pigment. The red colour of the blood stain was removed, however a yellow-brown colour and stiffness of the fabric remained. As phosphates are able to replace the oxide group in iron oxide (see section 1.2.3), a possible explanation for the absence of the iron oxide colour after the test is that the bicarbonate group in sodium bicarbonate (baking soda) replaced the oxide group in iron oxide, which has a yellow colour. (Wikipedia, 2008) F e2 O3 + 6N aHCO3 → 2F e(HCO3 )3 + 3N a2 O The results that showed that baking soda does not have redox potential may explain why it was not as effective as other cleaners in removing the other stains.

5.3

OMO Liquid

Although OMO Liquid was neutral and a poor conductor, it effectively cleaned five of the stains. Its effectiveness was most likely due to its redox potential and solubility in water, acid and base. Unlike most of the other stain removal solutions, OMO Liquid worked relatively well on the ink stain. OMO Liquid also worked well on the same stains as bleach, which suggests that contains a form of bleach or other oxidising agent.

5.4

Drive

Drive laundry detergent worked similarly to baking soda in that it only worked well on the beetroot and blood stains. The packaging of the laundry power suggested the use of warm water, which implies the possible presence of enzymes. As only cold water was used, it is possible that Drive was not able to work to its full potential. Drive did show some impact on the foundation stain. However, it was not soluble in oil, which suggests that the Drive was able to remove some other part of the foundation stain other than the oil - possibly part or one kind of pigment. 1

received a rating of 4 or greater in Table 2

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5.5

Napisan Oxy-Action

With its basic nature, high conductivity, redox potential and solubility in water, acid and base, Napisan Oxy-Action had an effect on all the stains. However, like most of the other stain removal solutions, Napisan Oxy-Action was not so good at removing the foundation and ink stains. Napisan Oxy-Action’s conductivity indicates that it contains ionic particles, and its redox potential (and effectiveness on the same stains as bleach) suggests that it contains solid sodium hypochlorate (bleach).

5.6

Bleach

Bleach was clearly the most efficient stain removal method. It is likely that the other cleaning solutions that worked fairly well on the same kinds of stains contained a small amount of some kind of bleach. As discussed in the background section, the hydrogen peroxide in bleach is a strong oxidising agent that is able to convert some of the double bonds in chromophores to single bonds through redox reactions, removing the chromophore’s ability to display colour. The sodium hyperchlorate and hydrogen peroxide in bleach can also liberate oxygen. N aOCl + H2 O2 O2 + N aCl + H2 O In this instance, the hydrogen peroxide acts as the reducing agent, and the oxygen that is produced from the reaction disturbs the stain particles and may dislodge them from the fibers of the fabric. One observation was that the bleach slightly discoloured the stark white cotton fabric of the square that had no stain applied to it. So the hydrogen peroxide even attacked the bright white chromophores in the fabric.

5.7

Lemon Juice

Lemon juice, in theory, should have been a very effective stain remover. However, it was only partially effective on some of the stains and ineffective on the rest. Because lemon juice contains both lemon oil and water, as well as acetic acid, it was soluble in water, oil, acid and base. However, the water-based lemon juice was suspended in the oil, and the lemon oil was suspended in the base, so it was only partially soluble in oil and base. Lemon juice also slightly discoloured the fabric which is probably due to its yellow pigment being left behind on the fabric.

5.8

Tap Water

Although water is considered a universal solvent, because stains are made up of several constituents of different chemical nature, water cannot always remove the stain entirely. For example, foundation which is made up of oils, pigments and opacifying agents which leave a heavy residue in the fibers of the fabric. The oils and chromophores that make up the pigment in foundation are non-polar and therefore cannot be dissolved in water. The particles of the opacifying agent were too heavy to be dislodged from the fabric by the water molecules. Water did not have great impact on any of the stains when used entirely by itself. However, every other laundry detergent and cleaning solution was water-based - water was a necessary ingredient in all the other stain removal solutions.

5.9

Overall

It would seem from the results that baking soda was chemically similar to Drive. They both worked on the same stains to a similar extent, however, their pH, conductivity, solubility and redox potential were different. So they are most likely not chemically similar, however, their chemical constituents work on similar parts of the same stains.

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It also seems that Sard Wonder Soap, OMO Liquid, Napisan Oxy-Action and bleach all have similar chemical constituents. As they all have redox potential and are soluble in bases, it is likely that Sard Wonder Soap, OMO Liquid and Napisan Oxy-Action contain some form of bleach. However, Sard Wonder Soap was most likely the only laundry detergent that contained surfactants as it was the only stain remover that had a real effect on the foundation and ink stains. Lemon juice and tap water were not very effective at removing any of the stains in the stain test. This is probably because water only has the attribute of polar molecules that are only able to dissolve other polar molecules, and lemon juice contains oil and citric acid which only allow it to dissolve oil-based and acidic stains. All the stain removers except for lemon juice and tap water were able to effectively remove blood stains, which indicated the presence of phosphates. There were not any anomalous results. The toughest stains are those that contained pigments, which only stain removers containing bleach or other oxidising agents were able to remove. Blood was able to be removed by stain removers that contained phosphates. Heavy, oil-based stains such as that of foundation and ink required surfactants (only present in Sard Wonder Soap) in order to be removed.

Table 3: User’s guide to cleaning stains Stain Type Best Cleaners Coffee Bleach, Napisan Oxy-Action Beetroot Bleach, Napisan Oxy-Action Blood Bleach, OMO Liquid Grass Bleach, Napisan Oxy-Action Red Wine Bleach, Napisan Oxy-Action Foundation Sard Wonder Soap Black Ink Sard Wonder Soap

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6

Conclusion

The data collected from the five experiments in this extended experimental investigation were quite comprehensive. This provided enough chemical information about the stain removal solutions to be able to draw conclusions about the chemical mechanisms of stain removal present throughout the investigation. However, there were some procedural inaccuracies that could have been further improved. Warm water is sometimes required of laundry detergents in order for them to work properly. As discussed in the background section of this paper, an increase in temperature provides the molecules of both the stain and the cleaner with more energy, causing them to vibrate and move around more. By providing the particles with more energy, redox reactions and dissolvation occurs more rapidly and is therefore more effective. Only cold water was used during the investigation because the stains were left to soak for such a long period of time, so it is possible that not all the laundry detergents worked to their full potential. An improvement to the method of the stain experiment would have been to use warm or hot water instead of cold. The concentrations of the stain removal solutions used in this investigation were not of the same concentration that would be used in a load of washing. This could have provided misleading results. However, the concentrations were actually higher than if the were the true concentrations used in a load of washing. If the results were affected in any way, they were only made clearer because the concentration would have been high enough for the chemicals that did actually work on the stain to work to their full potential (disregarding temperature), while the parts of the stain that could not be removed by the cleaner remained on the fabric at the end of the cleaning test. This investigation could have been improved by testing a wider variety of cleaning solutions on more kinds of stains. Also, the presence of true enzymes (as opposed to oxidising agents) could be investigated. Further separation of the chemical constituents of the laundry detergents could be done in order to identify particular ingredients, their chemical properties, and role in stain removal. Overall, the investigation provided accurate results that allowed the identification of different types of stain removal solutions constituents and how they assisted in the removal of certain parts of different kinds of stains.

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References [1] Calder, V. (2008) ”Stain Removal”, Ask A Scientist, Argonne http://www.newton.dep.anl.gov/askasci/chem00/chem00229.htm (23/08/08)

National

Laboratory,

[2] Calder, V. (2008) ”Ethanol as a Stain Remover”, Ask A Scientist, Argonne National Laboratory, http://www.newton.dep.anl.gov/askasci/chem07/chem07002.htm (23/08/08) [3] Calder, V. (2008) ”Bonds and Stains on Fabrics”, Ask A Scientist, Argonne National Laboratory, http://www.newton.dep.anl.gov/askasci/chem03/chem03660.htm (23/08/08) [4] Calder, V. (2008) ”Measuring Stain Intensity”, Ask A Scientist, Argonne National Laboratory, http://www.newton.dep.anl.gov/askasci/chem03/chem03813.htm (23/08/08) [5] Calder, V. (2008) ”Phosphate and Stain Removal”, Ask A Scientist, Argonne National Laboratory, http://www.newton.dep.anl.gov/askasci/chem03/chem03735.htm (23/08/08) [6] Cross, J. (2006) ”The makeup of the toughest http://www.cleanprosonline.com/Toughest stains.html (10/09/08)

stains”,

CleanPros

Online,

[7] Donker, C.B. (1998) Non-aqueous Liquid Cleaning Products Which Contain Modified Silica, US Patent vol.5, no.714, pp.449. [8] Moore, J. W. (1999) ”Redox Titration and Animation”, Chemistry Comes Alive, Division of Chemical Education, Inc., American Chemical Society., http://jchemed.chem.wisc.edu/JCESoft/CCA/CCA3/MAIN/TITREDO/PAGE1.htm (01/09/08) [9] Rainbow International (2007) ”Spot and Stain Removal Guide”, Rainbow International Restoration and Cleaning, http://www.rainbowintl.com/expert/guide.aspx?c (10/09/08) [10] Szczepanski, A. (2008) Personal correspondence. [11] Wikipedia (2008) Micelle, Wikipedia, http://www.wikipedia.org/wiki/Micelle (23/08/08) [12] Wikipedia (2008) Surfactant, Wikipedia, http://www.wikipedia.org/wiki/Surfactant (23/08/08) [13] Wikipedia (07/09/08

(2008)

Redox Indicator,

Wikipedia,

http://www.wikipedia.org/wiki/RedoxIndicator

[14] Wikipedia (2008) Chromophore, Wikipedia, http://en.wikipedia.org/wiki/Chromophore (15/09/08) [15] Wikipedia (2008) Bleach, Wikipedia, http://en.wikipedia.org/wiki/Bleach (15/09/08) [16] Wikipedia (2008) Tannin, Wikipedia, http://en.wikipedia.org/wiki/Tannin (15/09/08) [17] Wikipedia (2008) FeCO3 , Wikipedia, http://en.wikipedia.org/wiki/Iron(II) carbonate (15/09/08) [18] Yamada, I. (2003) The difference between anionic and nonionic surfactant, and its appliation to detergent, Chemistry Question, http://www.chemistryquestion.com (07/09/08)

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A

Stain Removal Solutions’ Effectiveness on Different Stains

A.1

Aim

The aim of this experiment was to identify which stain removal solutions were able to remove which stains and how effectively the stains were removed.

A.2 • • • • • • • • •

Equipment and Materials

64× 50mL beakers 25mL Tap water 25mL Bleach 25mL Baking soda 25mL Lemon juice Coffee stain Blood Red Wine Black ink

A.3

• • • • • • • • •

25mL Sard Wonder Soap 25mL Omo Liquid 25mL Drive 25mL Napisan Oxy-action 64× 10cm×10cm white cotton squares Beetroot juice Grass Foundation Stirring rod

Procedure

1. Each of the stains (coffee, beetroot, blood, grass, red wine, foundation, black ink) were applied to 8 pieces of white cotton each and left to dry for 24 hours. 2. 8 50mL beakers were filled with Sard Wonder Soap solution which was made by adding 1g of shavings of the soap to 50mL of water in each beaker and stirring vigorously until all the soap was dissolved. 3. 8 50mL beakers were filled with baking soda solution which was made by dissolving 1g of baking soda in 50mL of tap water for each beaker. 4. 8 50mL beakers were filled with OMO Liquid solution which was made by adding 1mL of OMO Liquid to 50mL of tap water for each beaker. 5. 8 50mL beakers were filled with Drive solution which was made by adding 1g of laundry powder to 50mL of warm tap water for each beaker. (warm water was only used to assist with dissolving the powder in the water) 6. 8 50mL beakers were filled with Napisan Oxy-action solution which was made by adding 1g of laundry powder to 50mL of warm tap water for each beaker. (warm water was only used to assist with dissolving the powder in the water) 7. 8 50mL beakers were filled with bleach solution which was made by adding 10mL of bleach to 50mL of tap water for each beaker. 8. 8 50mL beakers were filled with 50mL of lemon juice. 9. 8 50mL beakers were filled with 50mL of tap water. 10. Once all the solutions were of room temperature, one of each of the stains and the control (no stain) were added to the 8 beakers containing Sard Wonder Soap solution, making sure that the entire fabric square was submerged in the stain removal solution. 11. Step 10 was repeated for the other 7 stain removal solutions (including water) so that a grid of test beakers was set up so each combination of stain and stain remover was tested.

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12. After the cotton squares were left to soak for 24 hours, they were rinsed in cold tap water.

A.4

Results

Table 4: Degree of stain removal (0 = no change, 5 = no trace) Coffee Beetroot Blood Grass Red Wine Foundation Ink None Sard Wonder Soap 4 5 4 4 4 3 2 5 Baking Soda 2 4 4 2 3 0 0 5 OMO Liquid 4 4.5 4.5 4 4 1 2 5 Drive 3 4.5 4 3 3 2 1 5 Napisan Oxy-Action 4.5 5 4 4.5 4.5 1 0.5 5 Bleach 5 5 5 5 5 0 0 4.5 Lemon Juice 3 3 2 2 2 0 0 4.5 Tap Water 3 3 3 1 3 0 0 5

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B

Determining the pH of the Stain Removal Solutions

B.1

Aim

The aim of this experiment was to determine the pH of each of the stain removal solutions.

B.2 • • • • • •

Equipment and Materials

8× 50mL beakers Distilled water 10mL Tap water 10mL Bleach solution 10mL Baking soda solution 10mL Lemon juice solution

B.3

• • • • • •

10mL Sard Wonder Soap solution 10mL Omo Liquid solution 10mL Drive solution 10mL Napisan Oxy-action solution Universal indicator Universal indicator pH colour chart

Procedure

1. Each if the stain removal solutions were prepared as in Experiment 1 (see Appendix A) 2. 10mL of each stain removal solution was poured into it’s own 50mL beaker. 3. The beakers were filled to the 20mL mark with distilled water. 4. 10 drops of universal indicator was added to each beaker. 5. The pH was identified by using the universal indicator pH colour chart to match the colour of the solution in each beaker to the corresponding pH on the chart.

B.4

Results Table 5: pH of Cleaning Solutions Cleaning solution Sard Wonder Soap Baking soda Omo Liquid Drive Napisan Oxy-action Bleach Lemon juice Tap water (control)

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pH 9 8 7 11 10 8 4 7

C

Conductivity of the Stain Removal Solutions

C.1

Aim

To determine the conductivity of the stain removal solutions.

C.2 • • • • • • •

Equipment and Materials

10× 50mL beakers Distilled water Stirring rod 25mL Tap water 25mL Bleach solution 25mL Baking soda solution 25mL Lemon juice solution

C.3

• • • • • • •

25mL Sard Wonder Soap solution 25mL Omo Liquid solution 25mL Drive solution 25mL Napisan Oxy-action solution 25mL 10% NaCl solution Conductivity testing apparatus 100mL beaker

Procedure

1. A beaker containing 25mL of distilled water was placed in the conductivity testing apparatus so that the electrodes were submerged. 2. The brightness of the light bulb was noted. This set the marker for the least conductive solution. 3. The electrodes were rinsed off with distilled water into the 100mL beaker. 4. Steps 1-2 were repeated for the beaker containing 25mL of NaCl solution. This set the marker for the most conductive solution. 5. The conductivity of the 8 stain removal solutions (Sard Wonder Soap, baking soda, Omo Liquid, Drive, Napisan Oxy-action, bleach, lemon juice and tap water) was tested by comparing and rating the light bulb’s brightness for each solution as an indicator of its conductivity.

C.4

Results

Table 6: Conductivity of Cleaning Solutions (0 = no conductivity, 5 = very high conductivity) Cleaning solution NaCl solution Distilled water Sard Wonder Soap Baking soda Omo Liquid Drive Napisan Oxy-action Bleach Lemon juice Tap water (control)

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Conductivity 5 0 2 5 1 3 4 4 4 1

D

Solubility of the Stain Removal Solutions

D.1

Aim

To determine the solubility of the stain removal solutions in water, oil, acids and bases.

D.2 • • • • • • • •

Equipment and Materials

32 test tubes Test tube rack Bamboo skewers Spatula 20mL Bleach solution 20mL Baking soda solution 20mL Lemon juice solution 20mL Sard Wonder Soap solution

D.3

• • • • • • •

20mL Omo Liquid solution 20mL Drive solution 20mL Napisan Oxy-action solution 80mL vegetable oil 80mL 0.1M HCl 80mL 0.1M NaOH Tap water

Procedure

1. 8 of the test tubes were filled with 10mL tap water each, 8 with vegetable oil, 8 with 0.1M HCl and 8 with 0.1M NaOH. 2. 5mL of each of the stain removal solutions was added to each of the solvents so that a test grid was made so that each combination of stain removal solution and solvent was tested. 3. Each of the mixtures in the test tubes were stirred vigorously with a bamboo skewer, using a different skewer in each test tube. 4. The test mixtures were left for 24hrs so that it was clear which solutions were dissolved and which were suspended.

D.4

Results Table 7: Solubility of Cleaning Solutions Cleaning solution Sard Wonder Soap Baking soda Omo Liquid Drive Napisan Oxy-action Bleach Lemon juice Tap water (control)

Water Oil X* X* X × X × X × X × X × X X*1 X ×

Acid × X X × X X X X

Base X X X X X X X*2 X

X = soluble, * = partially soluble, × = insoluble 1 Water-based lemon juice was suspended 2 Lemon oil was suspended

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E

Redox Indicator Test

E.1

Aim

The aim of this experiment was to identify the redox potential of each of the stain removal solutions.

E.2 • • • • • • •

Equipment and Materials 9× 50mL beakers Spatula Stirring rods 25mL Tap water 25mL Bleach 25mL Baking soda 25mL Lemon juice

E.3

• • • • • • •

25mL 25mL 25mL 25mL 25mL 50mL 50mL

Sard Wonder Soap Omo Liquid Drive Napisan Oxy-action 0.1M Hydrogen Peroxide (H2 02 ) 0.1M Hydrochloric Acid (HCl) Potassium Permanganate (KMnO4 )

Procedure

1. The cleaning solutions were prepared as in Experiment 1 (see Appendix A). 2. 25mL of 0.1M Hydrogen Peroxide was added to the remaining 50mL beaker as the control. 3. Acidified potassium permanganate was made by mixing 50mL of 0.1M HCl with 50mL of KMnO4 . 4. Even amounts of acidified potassium permanganate were added to each of the beakers containing the stain removal solutions as well as the control. 5. The solutions were observed over 30 minutes. The solutions that returned clear or to their original colour (ie. did not remain pink from the acidified potassium permanganate) were identified as having undergone a redox reaction and therefore had redox potential.

E.4

Results Table 8: Redox Potential Test Cleaning solution Hydrogen Peroxide Sard Wonder Soap Baking soda Omo Liquid Drive Napisan Oxy-action Bleach Lemon juice Tap water (control)

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Redox Potential X X × X X X X X ×