Give simple chemical tests to distinguish between the following pairs of compounds.
(i) Propanal and Propanone     (ii) Acetophenone and Benzophenone
(iii) Phenol and Benzoic acid                   (iv) Benzoic acid and Ethyl benzoate
(v) Pentan-2-one and Pentan-3-one       (vi) Benzaldehyde and Acetophenone
(vii) Ethanal and Propanal

(i) Propanal and propanone :
Propanal gives silver mirror test with Tollen's reagent. Propanone does not gives this test.
Propanal gives red ppt with Fehlings solution but propanone does not give this test.

(ii) Acetophenone and Benzophenone :
Acetophenone gives yellow ppt of idoform with alkaline solution of iodine (iodoform test) and Benzophenone doe not give this test.

(iii) Phenol and Benzoic acid :
Phenol does not react with sodium hydrogen carbonate and benzoic acid gives effervescence of carbon dioxide gas upon reaction with sodium hydrogen carbonate.
Phenol gives violet colour with ferric chloride solution but benzoic acid does not give such colour.

(iv) Benzoic acid and Ethyl benzoate :
 Ethyl benzoate does not react with sodium hydrogen carbonate and benzoic acid gives effervescence of carbon dioxide gas upon reaction with sodium hydrogen carbonate.
When ethyl benzoate is boiled with excess NaOH, it gives ethanol. Ethanol on heating with iodine gives yellow ppt of iodoform. This test is not given by benzoic acid.

(v) Pentan-2-one and Pentan-3-one  :
Pentan-2-one gives iodoform test and Pentan-3-one  does not gives iodoform test
Pentan-2-one gives white ppt with sodium bisulphite whereas pentan-3-one  does not give ppt.

(vi) Benzaldehyde and Acetophenone :
Benzaldehyde forms silver mirror with ammoniacal silver nitrate solution (Tollen\s reagent) and Acetophenone does not give this test.
Acetophenone gives iodoform test. Benzaldehyde does not react.

(vii) Ethanal and Propanal :
Ethanal gives iodoform test but propanal does not give such test.