Question

Two compounds A and B react with each other in the presence of a dehydrating agent to produce an

ester. 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

ESTERIFICATION REACTION:
Ethanoic acid reacts with Ethanol  on warming in presence of a few drops of conc. H2SO4 to form a sweet smelling ester.
                                       
CH3COOH   + C2H5OH -------------->CH3COOC2H5 + H2O

SO A AND B ARE   ETHANOIC ACID and ETHANOl.

Both compounds A and B react with sodium metal to evolve Hydrogen gas.
Chemical Reaction:
2C2H5OH+2Na ----->2C2H5O⁻Na⁺  + H2

Compound A reacts with Na2CO3 TO EVOLVE CO2 GAS
2CH3COOH + Na2CO3 -----> 2CH3COONa  + CO2  +H2O

 So from the above chemical reaction we can see clearly compound A belongs to carboxylic acid functional group [COOH] and compound B belongs to alcohol  functional group[OH].