Q27 of 30 Page 1

(a) Which one of the following is a food preservative?

Equanil, Morphine, Sodium benzoate


(b) Why is bithional added to soap?


(c) Which class of drugs is used in sleeping pills?


(a) Sodium benzoate is used as a food preservative whereas equanil is used as tranquilizer and morphine an analgesic.


(b) Bithional has antiseptic properties and so it is added to soaps to reduce the bad odour produced by bacterial decomposition of organic matter on the skin that is to keep us fresh.


(c) Tranquilizers are sedatives which can are useful in treating anxiety, recovering from the symptoms of stress and inducing sleep. So, they are used in sleeping pills.


More from this chapter

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25

Write the names and structures of the monomers of the following polymers:

(i) Buna-S


(ii) Neoprene


(ii) Nylon-6,6


 26

After watching a programme on TV about the adverse effects of junk food and soft drinks on the health of school children, Sonali, a student of Class XII, discussed the issue with the school principal. Principal immediately instructed the canteen contractor to replace the fast food with the fibre and vitamins rich food like sprouts, salad, fruits etc. This decision was welcomed by the parents and the students.

After reading the above passage, answer the following questions:


(a) What values are expressed by Sonali and the Principal of the school?


(b) Give two examples of water-soluble vitamins.


 28

(a) A reaction is second order in A and first order in B.

(i) Write the differential rate equation.


(ii) How is the rate affected on increasing the concentration of A three times?


(iii) How is the rate affected when the concentrations of both A and B are doubled?


(b) A first order reaction takes 40 minutes for 30% decomposition. Calculate t1,2 for this reaction.


(Given log 1.428 =0.1548)


OR


(a) For a first order reaction, show that time required for 99% completion is twice the time required for the completion of 90% of reaction.


(b) Rate constant 'k' of a reaction varies with temperature 'T' according to the equation:



Where, Ea is the activation energy. When a graph is plotted for log k Vs. a straight line with a slope of –4250 K is obtained. Calculate 'Ea' for the reaction.


(R = 8.314 JK–1 mol-1).


29

(a) Give reasons for the following:

(i) Bond enthalpy of F2 is lower than that of Cl2.


(ii)PH3 has lower boiling point than NH3.


(b)Draw the structures of the following molecules:


(i)BrF3


(ii)(HPO3)3


(iii)XeF4


OR


(a) Account for the following:


(i) Helium is used in diving apparatus.


(ii) Fluorine does not exhibit positive oxidation state.


(iii)Oxygen shows catenation behavior less than sulphur.


(b)Draw the structures of the following molecules:


(i)XeF2


(ii)H2S2O8