Question

A carbon compound X turns blue litmus to red and has a molecular formula C2H4O2.Identify X and draw its structure.Write a chemical equation for the reaction and name of the product formed in each case when X reacts with

a) ethanol in the presence of conc.H2SO4

(b) sodium carbonate

Answer 1

Compound X is CH3COOH I.e acetic acid or ethanoic acid



H O
I II
H-C -C-OH
I
H


CH3COOH +C2H5OH→CH3COOC2H5 + H20 ethyl acetate

2CH3COOH + NA2CO3→2CH3COONA +H20 +CO2↑ sodium ehanoate

Done..........

Answer 2

Ethanoic acid

Explanation:

The compound X, C2H4O2, is capable of converting ​ blue litmus to red, so it is an acid.  

In general, carboxylic acids, phenols and sulphonic acids are acididc in nature. As the given molecular formula does not include sulphur, the probablity of sulphonic acids is negligible. The given compound is not a phenol as we require minium six carbons. Hence, the given compound is a carboxylic acid.

The structure of X is CH3COOH (rearranging C2H4O2 with the required functional group). Hence the compound X is Ethanoic acid.

a) Ethanoic acid in presence of concentrated sulphuric acid gives:

CH3COOH + CH3CH2OH --> CH3COOCH2CH3 + H2O

b) Acetic acid reacts with sodium carbonate as below:

2CH3COOH + Na2CO3 --> 2CH3COONa + CO2 + H2O