English Medium Class 10 - CBSE Question Bank Solutions

How is ethanol to ethanoic acid an oxidation reaction different from the reaction in which ethanol burns in the presence of oxygen?

List two roles of Seminal vesicles and prostate gland in the human reproductive system.

List two roles of the Testis in the human reproductive system.

Mention the functions of Uterus in the human female reproductive system.

Both soap and detergent are some type of salts. What is the difference between them?

Describe in brief the cleansing action of soap.

Why do soaps not form lather in hard water?

List two problems that arise due to the use of detergents instead of soaps.

While preparing soap a small quantity of common salt is generally added to the reaction mixture of vegetable oil and sodium hydroxide. Which one of the following may be the purpose of adding common salt?

(A) To reduce the basic nature of the soap

(B) To make the soap neutral

(C) To enhance the cleansing power of the soap

(D) To favour the precipitation of the soap

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

In the neighbourhood of your school, hard water required for an experiment is not available. Select from the following group of salts available in your school, a group each member of which, if dissolved in distilled water, will make it hard:

(a) Sodium chloride, calcium chloride

(b) Potassium chloride, sodium chloride

(c) Sodium chloride, magnesium chloride

(d) Calcium chloride, magnesium chloride

Which of the following sets of materials can be used for conducting a saponification reaction for the preparation of soap?

(a) Ca(OH)₂ and neem oil

(b) NaOH and neem oil

(c) NaOH and mineral oil

(d) Ca(OH)₂ and mineral oil

A student takes four test tubes marked P, Q, R and S of 25 mL capacity and fills 10 mL of distilled water in each. He dissolves one spoon full of four different salts in each as − KCl in P, NaCl in Q, CaCl₂ in R and MgCl₂ in S. He then adds about 2 mL of a sample of soap solution to each of the above test tubes. On shaking the contents of each of the test tubes, he is likely to observe a good amount of lather (foam) in the test tubes marked

(a) P and Q

(b) R and S

(c) P, Q and R

(d) P, Q and S

Hard water is not available for an experiment. Some salts are given below :

(I) Sodium chloride

(II) Sodium sulphate

(III) Calcium chloride

(IV) Calcium sulphate

(V) Potassium chloride

(VI) Magnesium sulphate

Select from the following group of these salts, each member of which may be dissolved in water to make it hard.

(A) I, II, V

(B) I, III, V

(C) III, IV, VI

(D) II, IV, VI

Would you be able to check if water is hard by using a detergent?

People use a variety of methods to wash clothes. Usually after adding the soap, they ‘beat’ the clothes on a stone, or beat it with a paddle, scrub with a brush or the mixture is agitated in a washing machine. Why is agitation necessary to get clean clothes?

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.

What change will you observe if you test soap with litmus paper (red and blue)?