Class 10 Exam  >  Class 10 Notes  >  To study the comparative cleaning capacity of a sample of soap in soft and hard water.

To study the comparative cleaning capacity of a sample of soap in soft and hard water. - Class 10 PDF Download

to study the comparative cleaning capacity of a sample of soap in soft and hard water

Ref: https://edurev.in/question/739865/to-study-the-comparative-cleaning-capacity-of-a-sample-of-soap-in-soft-and-hard-water-Related-To-obs

Aim

To study the comparative cleaning capacity of a sample of soap in soft and hard water.

Theory
To study the comparative cleaning capacity of a sample of soap in soft and hard water. - Class 10 
Hardness of water is caused by the presence of the salts of calcium and magnesium (hydrogencarbonates, chlorides and sulphates) in water. These salts are soluble in water. When soap is added to hard water, it reacts with the salts to form a scum, which is insoluble and floats on top of the water surface. The scum is formed due to the formation of insoluble calcium or magnesium salts of the fatty acid used in the soap formation. The soap in solution then becomes ineffective.Ca(HCO 3)2 (aq) + 2Na+ -stearate (aq) ⎯→ Ca(stearate)2 (s) + 2NaHCO3 (aq)
CaSO4 (aq) + 2Na+ -stearate (aq) ⎯→ Ca(stearate)2 (s) + Na2SO4 (aq)
The salts of calcium and magnesium show similar reactions. Therefore, the presence of calcium and magnesium salts in water precipitates the soap thereby reducing its cleansing power and foaming capacity.


Materials Required
Underground water (well water), distilled water, calcium hydrogencarbonate or calcium sulphate, soap sample, a physical balance and weight box, three test tubes and a test tube stand, three beakers (100 mL), three glass rods, a measuring cylinder (50 mL), and a measuring scale,

Procedure




To study the comparative cleaning capacity of a sample of soap in soft and hard water. - Class 10
Step 1: Three beakers are taken and labelled as A, B and C.
Step 2: 20 mL of distilled water is taken in beaker A. In beaker B, 20 mL of underground water is put, and 2 g of calcium hydrogencarbonate (or calcium sulphate) is added in beaker C to 20 mL of distilled water.
Step 3: The contents of beaker C is stirred so that calcium hydrogen carbonate (or calcium sulphate) dissolves in water.
Step 4: 1 g of soap is put in each beaker A, B, and C (after weighing it using a physical balance).
Step 5: The contents of these beakers are stirred with separate glass rods.
Step 6: Three test tubes are placed in a test tube stand and labelled as tube A, B and C.
Step 7: 3 mL of the above prepared soap solution is poured in the corresponding test tubes.
Step 8: Test tube A is taken and shaken ten times by placing thumb on its mouth.
Step 9: Foam or lather is formed by shaking the test tube. The length of the foam produced is measured immediately with the help of a measuring scale.
Step 10: Similarly, steps 8 and 9 are repeated with the remaining two samples.

Observations
(i) Mass of the soap sample taken in each beaker = _____ g
(ii) Volume of the distilled water and underground water = _____ mL
added in each beaker
(iii) Volume of soap sample taken in each test tube =  _____  mL
(iv) Number of times each test tube taken =  _____

Results and Discussions
Infer from the observations that which solution of the soap sample produces the maximum length of foam (lather). For cleansing purpose, the foam needs to be produced which depends on free availability of hydrophobic portion of soaps (or alkyl groups). In hard water it is trapped due to scum or precipitation, this makes the hard water unsuitable for washing.

Precautions
1. Use same sample of soap for soft water and hard water.
2. Stir the mixture carefully while dissolving soap in water so as to avoid spilling of soap solution.
3. The quantity of soap sample in all solutions must be same. The amount of distilled water added in every soap sample must be same. That is the concentration of all test solutions must be same.
4. The mass of the soap samples must be determined very carefully using a physical balance. In case of any need, take help from your teacher.
5. Shake every tube for equal number of times and in a similar manner.
6. Measure the length of the foam produced immediately after its production.
The document To study the comparative cleaning capacity of a sample of soap in soft and hard water. - Class 10 is a part of Class 10 category.
All you need of Class 10 at this link: Class 10

Top Courses for Class 10

FAQs on To study the comparative cleaning capacity of a sample of soap in soft and hard water. - Class 10

1. What is the purpose of studying the comparative cleaning capacity of soap in soft and hard water?
Ans. The purpose of this study is to determine how effective a particular soap is in cleaning under different water conditions. Soft water contains fewer minerals, while hard water has a high mineral content. By comparing the cleaning capacity in both types of water, we can assess the soap's performance and suitability for various regions.
2. How does soap interact differently with soft and hard water?
Ans. Soap interacts differently with soft and hard water due to the presence of minerals. In soft water, soap forms a lather easily and effectively removes dirt and grime. However, in hard water, the minerals react with soap to form insoluble compounds called soap scum. This reduces the soap's cleaning ability, making it less effective in hard water.
3. What factors affect the cleaning capacity of soap in different water types?
Ans. Several factors affect the cleaning capacity of soap in different water types. The mineral content of water, pH level, temperature, and the type of soap used all play a role. Soap works best in soft water with low mineral content and a slightly alkaline pH. Higher temperatures also enhance the cleaning capacity of soap.
4. Can the cleaning capacity of soap be improved in hard water?
Ans. Yes, the cleaning capacity of soap can be improved in hard water by using certain techniques or additives. One method is to increase the pH level of the water by adding baking soda or borax. This helps to counteract the effects of the minerals and allows soap to lather more effectively. Another option is to use soap specifically formulated for hard water, which contains ingredients that prevent soap scum formation.
5. How can the results of this study be applied in real-life situations?
Ans. The results of this study can be applied in real-life situations to guide the selection of soap for different water types. For areas with soft water, any soap can be used effectively. However, in regions with hard water, it is advisable to choose soaps that are specifically designed for hard water conditions. This can ensure better cleaning performance and prevent the accumulation of soap scum.
Download as PDF
Explore Courses for Class 10 exam

Top Courses for Class 10

Signup for Free!
Signup to see your scores go up within 7 days! Learn & Practice with 1000+ FREE Notes, Videos & Tests.
10M+ students study on EduRev
Related Searches

mock tests for examination

,

Previous Year Questions with Solutions

,

Free

,

Sample Paper

,

To study the comparative cleaning capacity of a sample of soap in soft and hard water. - Class 10

,

Objective type Questions

,

video lectures

,

ppt

,

past year papers

,

study material

,

Important questions

,

Exam

,

To study the comparative cleaning capacity of a sample of soap in soft and hard water. - Class 10

,

pdf

,

Semester Notes

,

MCQs

,

Extra Questions

,

practice quizzes

,

Summary

,

shortcuts and tricks

,

To study the comparative cleaning capacity of a sample of soap in soft and hard water. - Class 10

,

Viva Questions

;