Chemistry Class 12 NCERT Solutions: Chapter 16 Chemistry in Everyday Life Part 2

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Q: 10. How do antiseptics differ from disinfectants? Give one example of each.

Answer:

Antiseptics and disinfectants are effective against microorganisms. However, antiseptics are applied to the living tissues such as wounds, cuts, ulcers, and diseased skin surfaces, while disinfectants are applied to inanimate objects such as floors, drainage system, instruments, etc. Disinfectants are harmful to the living tissues.

Iodine is an example of a strong antiseptic. Tincture of iodine (2 − 3 percent of solution of iodine in alcohol − water mixture) is applied to wounds. 1 percent solution of phenol is used as a disinfectant.

Q: 11. Why are cimetidine and ranitidine better antacids than sodium hydrogen carbonate or magnesium or aluminium hydroxide?

Answer:

Antacids such as sodium hydrogen carbonate, magnesium hydroxide, and aluminium hydroxide work by neutralization the excess hydrochloric acid present in the stomach. However, the root cause for the release of excess acid remains untreated.

Cimetidine and ranitidine are better antacids as they control the root cause of acidity. These drugs prevent the interaction of histamine with the receptors present in the stomach walls. Consequently, there is a decrease in the amount of acid released by the stomach. This is why cimetidine and ranitidine are better antacids than sodium hydrogen carbonate, magnesium hydroxide, and aluminium hydroxide.

Q: 12. Name a substance which can be used as an antiseptic as well as disinfectant.

Answer:

Phenol can be used as an antiseptic as well as a disinfectant. 0.2 percent solution of phenol is used as an antiseptic, while 1 per cent of its solution is used as a disinfectant.

Q: 13. What are the main constituents of dettol?

Answer:

The main constituents of dettol are chloroxylenol and .

Q 13 Structure of Chloroxylenol and α-terpineol

Q 13 Structure of Chloroxylenol and Α-Terpineol

Q 13 Structure of Chloroxylenol and α-terpineol

Q: 14. What is tincture of iodine? What is its use?

Answer:

Tincture of iodine is a 2 − 3 percent solution of iodine in alcohol − water mixture. It is applied to wounds as an antiseptic.

Q: 15. What are food preservatives?

Answer:

Food preservatives are chemicals that prevent food from spoilage due to microbial growth. Table salt, sugar, vegetable oil, sodium benzoate , and salts of propanoic acid are some examples of food preservatives.

Q: 16. Why is use of aspartame limited to cold foods and drinks?

Answer:

Aspartame becomes unstable at cooking temperature. This is the reason why its use is limited to cold foods and drinks.

Q: 17. What are artificial sweetening agents? Give two examples.

Answer:

Artificial sweetening agents are chemicals that sweeten food. However, unlike natural sweeteners, they do not add calories to our body. They do not harm the human body. Some artificial sweeteners are aspartame, saccharin, sucralose, and alitame.

Q 17 Artificial Sweetener

Q 17 Artificial Sweeteners

Q 17 Artificial Sweetener

Q: 18. Name a sweetening agent used in the preparation of sweets for a diabetic patient.

Answer:

Artificial sweetening agents such as saccharin, alitame, and aspartame can be used in preparing sweets for diabetic patients.

Q: 19. What problem arises in using alitame as artificial sweetener?

Answer:

Alitame is a high potency sweetener. It is difficult to control the sweetness of food while using alitame as an artificial sweetener.

Q: 20. How are synthetic detergents better than soap?

Answer:

Soaps work in soft water. However, they are not effective in hard water. In contrast, synthetic detergents work both in soft water and hard water.

Therefore, synthetic detergents are better than soaps.