Advertisements
Advertisements
प्रश्न
Why do soaps not work effectively in hard water?
उत्तर
Calcium and magnesium ions can be found in hard water. In hard water, these ions displace sodium or potassium from the salts that make up soaps, forming insoluble calcium or magnesium salts of fatty acids. As scum, these insoluble salts separate. This explains why soap does not dissolve in hard water.
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
Why does micelle formation take place when soap is added to water? Will a micelle be formed in other solvents such as ethanol also?
Explain the formation of scum when hard water is treated with soap.
Explain the process of preparation of soap in laboratory.
Describe the structure of a soap molecule with the help of a diagram.
Explain the cleansing action of soap. Draw diagrams to illustrate your answer.
The chemical which is not required for the preparation of soap in the laboratory is:
(a) vegetable oil
(b) baking soda
(c) caustic soda
(d) common salt
A student is testing water to know which is best for cleansing purposes with soaps. He would find that the cleansing action of soaps is best when he uses water obtained from
(a) rain
(b) tap
(c) hand pump
(d) pond
Explain why synthetic detergents are superior to soap.
- Write the formula and draw electron dot structure of carbon tetrachloride.
- What is saponification? Write the reaction involved in this process.
