(a) (i) Give reasons for the following : [3] (I) Covalent compounds are poor conductor of electricity. (II)…
(a) (i) Give reasons for the following : [3]
(I) Covalent compounds are poor conductor of electricity.
(II) Soap does not form lather in hard water.
(III) Carbon shows catenation but silicon does not.
(ii) Write chemical equations for the following : [2]
(I) Oxidation of ethanol by acidified K2Cr2O7.
(II) Hydrogenation of ethene.
Solution
(a) (i)
(I) They do not give rise to charged particles/ ions.
(II) Soap reacts with calcium and magnesium salts present in
hard water and forms insoluble substances called Scum.
(III) C-C bonds are strong and stable whereas Si-Si bonds are
relatively weak.
acidified K2 Cr2 O7 +heat
(ii) (I) CH3 CH2 OH → CH3 COOH
Ni
(II) CH2 =CH2 + H2 → CH3 -CH3
OR
(b) (i) X - CH3COOH/ethanoic acid /acetic acid
Y - CH3COOC2H5/CH3COOCH2CH3/ ester/ ethyl ethanoate
Z - CH3COONa/sodium ethanoate/sodium acetate
(ii) Catalyst/ dehydrating agent
PAGE 7 {31/1/1}
(iii)
•
• Esterification reaction
• CH3 COOC2 H5 + NaOH → CH3 COONa +C2 H5 OH
• Saponification reaction/ De-esterification reaction
SECTION – C
(Physics)