Question

Give simple chemical tests to distinguish between the following pairs of compounds: Phenol and Benzoic acid

Answer 1

HELLO DEAR,

THIS MAY BE DISTINGUISHED AS FOLLOWS;

( 1 ) $\bold{NaHCO_3\; test.}$ benzoic acid being a stronger acid than carbonic acid (H2CO3) decomposes(NaHCO3) to evolve CO2 but phenol being a weaker acid and carbonic acid does not.

$\bold{C_6H_5COOH + NaHCO_3 \longrightarrow C_6H_5COONa + CO_2\uparrow + H_2O}$

$\bold{C_6H_5OH + NaHCO_3 \longrightarrow No \;evolution \;of\; CO_2}$

( 2 ) . $\bold{FeCl_3\; tet.}$ phenol gives a voilet colouration with neutral $\bold{FeCl_3}$ while benzoic acid gives buff coloured PPT. of ferric benzoate.

$\bold{C_6H_5OH + FeCl_3 \longrightarrow voilet colouration}$

$\bold{3C_6H_5COOH + FeCl_3 \longrightarrow (C_6H_5COO)_3Fe + 3HCl}$

I HOPE IT'S HELP YOU DEAR,
THANKS

Answer 2

Answer:

phenol reacts with the ferric chloride and Iron phenol complex which is violet in colour whereas the benzoic acid does not give this test.