Q22 of 26 Page 1

(a) Why is it safer to use soaps from the environmental point of view?


(b) What is the basic difference between antiseptics and disinfectants?


(c) Pickles have a long shelf life and do not get spoiled for months. Why?


(a) It s safer to use soaps from the environmental point of view as they are less branched than detergents which make them less stable and easily biodegradable.


(b) The antiseptics can be used on living cells or tissue to prevent or cure septic infections and kill any pathogen (disease causing organisms) whereas disinfectants are used on non living things and surfaces to make them free from any infection causing germs.


(c) Pickles contain plenty of oil which acts like hydrophobic surface which keeps away the moisture. Also the added salt, absorbs any moisture, and act like preservative which don’t let any bacteria grow in pickle and prevent it from spoilage and make its shell life longer.


More from this chapter

All 26 →
20

Give reasons for the following :

(a) Methyl amine in aqueous solution gives reddish brown precipitate with ferric chloride (FeCl3).


(b) Ethyl amine is a stronger base than ammonia.


(c) (CH3)3C—NH2 has a lower boiling point than CH3CH2CH2CH2 — NH2 although both are isomeric in nature.


 21

(a) Identify the monomer units of


(b) On the basis of forces between their molecules in a polymer, which class do polyvinyls belong to ?


(c) Write the monomers of Terylene.


 23

Sanjay, a peon working in Mr. Pamil’s office, fainted while standing outside his room. Mr. Pamil took him to the nearby hospital where he was diagnosed to be severely 'anaemic’. The doctor prescribed an iron rich diet and multivitamin supplement to him. Mr. Pamil supported his family to get the medicines. After 20 — 25 days he was diagnosed to be normal.

Answer the following questions:


(a) What values (two) are displayed by Mr. Pamil ?


(b) Name the vitamin whose deficiency causes ‘Pernicious


Anaemia'.


(c) Give an example of a water soluble vitamin.


(d) Name two sources of vitamins needed to treat Pernicious Anaemia.


 24

(a) A solution is prepared by dissolving 5.0 g of a non-volatile solute in 95 g of water. It has a vapour pressure of 23.375 mmHg at 25°C. Calculate the molar mass of the solute. Vapour pressure of pure water at 25°C is 23.75 mmHg.

(b) Give reasons for the following :


(i) Osmotic pressure is considered to be a colligative property.


(ii) Molality is a better option to express concentration in comparison to molarity.


OR


(a) Calculate the amount of CaCl2 (molar mass = 111 g/mol) which must be added to 500 g of water to lower its freezing point by 2K, assuming CaCl2 is completely dissociated.


(Kf For water = 1.86 K kg /mol )


(b)


(i) What happens when blood cells are placed in distilled water?


(ii) Why is increase in temperature observed on mixing chloroform with acetone?