Question

Two compounds A and B react with each other in the presence of a dehydrating agent to produce anester. Both react with Na to evolve hydrogen gas. On reaction with Na2CO3 only A evolves CO2.Identify the functional groups present in A and B giving reason for your answer.

Answer 1

A-carboxylic group because ethanoic acid reacts with sodium carbonate to give sodium ethanol and CO2 and H20.
B-alcohol don't give CO2 with sodium carbonate.

Answer 2

A - CH3COOH (ethanoic acid)
functional group-carboxylic acid(because ethanoic acid reacts with sodium carbonate to give sodium ethanoate ,CO2 and H2O.)
B - CH3CH2OH (ethanol)
functional group-alcohol(because it does not react with sodium carbonate to give sodium ethanoate ,CO2 and H2O)

1)CH3COOH + CH3CH2OH ----conc.H2SO4---->CH3COOCH3CH2 + H2O
                                                                         (ethyl ethanoate)

2)→2CH3COOH + 2Na --------->2CH3COONa + H2
                                              (sodium ethanoate)

   →CH3CH2OH + Na   --------->CH3CH2ONa + H2
                                                (sodium ethoxide)

3)CH3COOH + Na2CO3 -----------> CH3COONa + CO2 + H2O
                                                        (sodium ethanoate)