Q26 of 26 Page 1

An organic compound (A) on treatment with ethyl alcohol gives a carboxylic acid (B) and a compound (C). Hydrolysis of (C) under acidic conditions gives (B) and (D). (B) upon heating with Ca(OH)2 gives (E), C3H6O. Identify A, B, C, D and E.

OR


(a) How are the following obtained?


(i) Benzaldehyde from Benzoylchloride


(ii) Acetone from propan-2-ol


(b) Give chemical tests to distinguish between the following pairs of compounds.


(i) Pentan-2-one and Pentan-3-one


(ii) Benzaldehyde and Acetophenone


(c) Carboxylic acids do not give characteristic reactions of carbonyl group. Why?


S

A = acetic anhydride (CH3COO)2O


B = acetic acid, CH3COOH


C = ethyl acetate, CH3COOC2H5


D = ethanol, C2H5OH


E = acetone, CH3COCH3



OR


(a) (i)



(ii)


(b) (i) Pentan-2-one and Pentan-3-one can be distinguished by iodoform test. Aldehydes or ketones having at least one methyl group linked to the carbonyl carbon atom are oxidized by NaOI.


Pentan-2-one have one methyl group attached to carbonyl carbon so it reacts with NaOI and gives yellow ppt of CHI3 whereas there is no methyl group attached to carbonyl carbon in Pentan-3-one so it does not give this test.



(ii) Benzaldehyde and Acetophenone can be distinguished by iodoform test. Aldehydes or ketones having at least one methyl group linked to the carbonyl carbon atom are oxidized by NaOI.


Acetophenone have one methyl group attached to carbonyl carbon so it reacts with NaOI and gives yellow ppt of CHI3 whereas there is no methyl group attached to carbonyl carbon in Benzaldehyde so it does not give this test.



(c) Carboxylic acids do not give characteristic reactions of carbonyl group because of resonance stabilisation of carboxylate ion as shown below. Due to this there is no nucleophilic addition reaction on carbonyl group of carboxylic acid and therefore, it do not give characteristic reactions of carbonyl group.



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22

Define the following terms:

(i) Antacids (ii) Antiseptic (iii) Tranquillizers


 23

Sheela, domestic helper of Mrs. Vimla, fainted while sweeping the floor. Mrs. Vimla immediately took her to the nearby hospital where she was diagnosed to be severely anaemic. The doctor prescribed an iron rich diet and multi vitamins supplement to her. Mrs. Vimla supported her financially to get the medicines. After a month, Sheela was diagnosed to be normal.

After reading the above passage, answer the following questions.


(i) Name the vitamin whose deficiency causes pernicious anaemia.


(ii) What are vitamins and how are they classified?


(iii) What values (any two) are displayed by Mrs. Vimla?


 24

(a) Examine the given defective crystal:


Answer the following questions:


(i) Is the above defect stoichiometric or non-stoichiometric?


(ii) Write the term used for this type of defect. Give an example of the compound which shows this type of defect.


(iii) How does this defect affect the density of the crystal?


(b) Write two differences between amorphous solids and crystalline solids.


OR


(a) In terms of band theory, how are conductors different from semi conductors and insulators? Give one example of each.


(b) Why does the electrical conductivity of semi conductors increase with rise in temperature?


(c) What is the formula of a compound in which the element Y form hcp lattice and atom X occupies 1/3rd of octahedral voids?


 25

A translucent white waxy solid (A) on heating in an inert atmosphere is converted to its allotropic form (B). Allotrope (A) on reaction with aqueous KOH liberates highly poisonous gas (C) having rotten fish smell. With excess of chlorine forms (D), which on hydrolysis forms the compound (E). Identify the compounds A to E.

OR


Give reasons:


(i) H2S has a lower boiling point than H2O.


(ii) Reducing character decreases from SO2 to TeO2.


(iii) H2Te is the strongest reducing agent amongst all the hydrides of group 16 elements.


(iv) BiH3 is stronger reducing agent than SbH3.


(v) HF is not stored in glass bottles but is kept in wax coated glass bottles.