Advertisements
Advertisements
प्रश्न
Which of the two is better for washing clothes when the water is hard: soap or detergent? Give reason for your answer.
Advertisements
उत्तर
Detergent is better for washing clothes in hard water because it does not form insoluble magnesium or calcium salts (scum) on combining with the calcium or magnesium ions present in the hard water. Soap on the other hand reacts with these calcium and magnesium ions present in the hard water to form insoluble calcium and magnesium salts of fatty acids. Therefore, soaps don't lather easily in hard water, while detergents do.
APPEARS IN
संबंधित प्रश्न
A student takes about 4 ml of distilled water in four test tubes marked P, Q, R and S. He then dissolves in each test tube an equal amount of one salt in one test tube, namely sodium sulphate in P, potassium sulphate in Q, calcium sulphate in R and magnesium sulphate in S. After that he adds an equal amount of soap solution in each test tube. On shaking each of these test tubes well, he observes a good amount of lather (foam) in the test tube marked
(A) P and Q
(B) Q and R
(C) P, Q and S
(D) P, R and S
In a locality, hard water, required for an experiment, is not available. However, the following salts are available in the school laboratory:
1. Sodium sulphate
2. Calcium sulphate
3. Magnesium chloride
4. Sodium chloride
5. Calcium chloride
6. Potassium sulphate
Which of the above salts may be dissolved in water to obtain hard water for the experiment?
(A) 2, 3 and 5
(B) 1, 2 and 5
(C) 1, 2, 4 and 6
(D) 3 and 5 only
Why does micelle formation take place when soap is added to water? Will a micelle be formed in other solvents such as ethanol also?
State one use of saponification process.
Why is soap not suitable for washing clothes when the water is hard?
Give any two differences between soaps and detergents.
What is the advantage of detergents over soaps for washing clothes?
Explain the cleansing action of soap. Draw diagrams to illustrate your answer.
What is a soap?
Give a scientific explanation.
Soap forms a precipitate in hard water.
Answer the following question.
In three test tubes A, B, and C, three different liquids namely, distilled water, underground water and distilled water in which a pinch of calcium sulphate is dissolved, respectively are taken. Equal amount of soap Answer is added to each test tube and the contents are shaken. In which test tube will the length of the foam (lather) be longest? Justify your answer.
How will you check with the help of soap powder whether water is hard?
What is meant by ‘surface activity’?
What are the differences between Bath soap and soap for washing clothes?
Arrange the following statements in correct sequence
- Pour that solution into an empty matchbox, soap can be obtained after drying.
- Take the necessary quantity of water in a jar.
- Then add coconut oil drop by drop and stir it well.
- Add concentrated sodium hydroxide in the jar and allow it to cool.
- Try this soap to wash your hand kerchief.
- Cover your work area with old newspaper.
Why do soaps not work effectively in hard water?
What are soaps?
