NCERT Class XII Chemistry
Chapter - Aldehydes, Ketones and Carboxylic Acids
Questions with Solutions
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Question : 19
Total: 28
.An organic compound contains 69.77% carbon, 11.63% hydrogen and rest, oxygen. The molecular mass of the compound is 86. It does not reduce Tollens’ reagent but forms an addition compound with sodium hydrogensulphite and give positive iodoform test. Onvigorous oxidation it gives ethanoic and propanoic acid. Write the possible structure of the compound.
Solution:
(a) The given compound does not reduce Tollens’ reagent which implies that it is not an aldehyde.
(b) Positive iodoform test proves that it has aC H 3 −
−
(c) The oxidation products are indicative of the presence of 5 carbon atoms.
To find the exact molecular formula
%C = 69.77%, %H = 11.63%, %O = 100 – (69.77 + 11.63) = 18.6 %
C : H : O =
:
:
The structure based on inferences a, b and c is
H 3 C −
− C H 2 C H 2 C H 3
Reactions involved are :C H 3 −
− ( C H 2 ) 2 C H 3
+
(b) Positive iodoform test proves that it has a
(c) The oxidation products are indicative of the presence of 5 carbon atoms.
To find the exact molecular formula
%C = 69.77%, %H = 11.63%, %O = 100 – (69.77 + 11.63) = 18.6 %
The structure based on inferences a, b and c is
Reactions involved are :
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