(a) Give chemical tests to distinguish between

(i) Propanal and propanone,


(ii) Benzaldehyde and acetophenone.


(b) How would you obtain


(i) But-2-enal from ethanal,


(ii) Butanoic acid from butanol,


(iii) Benzoic acid from ethylbenzene?


OR


(a) Describe the following giving linked chemical equations:


(i) Cannizzaro reaction


(ii) Decarboxylation


(b) Complete the following chemical equations:



(a)


(i) Propanal and Propanone


Iodoform Test: Warm each compound with iodine and sodium hydroxide on a water bath.


Propanal: No yellow ppt is formed


Propanone: Yellow crystals of Iodoform are formed


(Fehling’s test can also be done)


(ii) Benzaldehyde and Acetophenone


Iodoform test: Warm each organic compound with iodine and sodium hydroxide solution.


Acetophenone: Yellow precipitates of iodoform are formedBenzaldehyde does not respond to this test



OR


(a)


(i) Cannizzaro reaction: Aldehydes which do not have an a-hydrogen atom, undergo self-oxidation and reduction reaction on treatment with concentrated alkali.



ii) Decarboxylation: Carboxylic acids lose carbon dioxide to form hydrocarbons when their sodium salts are heated with soda lime. The reaction is known as decarboxylation.



(b) The complete reactions are:



1