Question

Give chemical tests to distinguish between
(i) Isopropyl alcohol and n-propyl alcohol
(ii) Phenol and alcohol
(iii) Methyl ethanoate and ethyl ethanoate.

Answer 1

(i) Isopropyl alcohol gives yellow precipitate of iodoform on heating with `I_(2)` and `NaOH` solution while n-propyl does not. For details, consult section 8.
(ii) Phenol gives a characteristic violet/red colouration with neutral `FeCl_(3)` while alcohol (e.g., ethyl alcohol) does not repond to this test.
(iii) Both are esters and upon hydrolysis in the acidic medium, they form methanol and ethanol respectively.
`underset("Methyl ethanoate")(CH_(3)COOCH_(3))+H_(2)O overset(H^(+))(rarr) CH_(3)COOH+underset("Methanol")(CH_(3)OH)`
`underset("Ethyl ethanoate")(CH_(3)COOC_(2)H_(5))+H_(2)O overset(H^(+))(rarr) CH_(3)COOH+underset("Ethanol")(C_(2)H_(5)OH)`
Ethanol and methanol can be further distinguished by iodoform test (given by ethanol and not by methanol).