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

Answer: Substance X is ethanoic acid and the reactions are given below.

Explanation:

A compound having molecular formula of $C_2H_4O_2$ which turns blue litmus to red is considered as an acid.

The compound is ethanoic acid which is generally termed as acetic acid.

Thus, the compound X is acetic acid.

The chemical equations for the reaction of X with

• a. Ethanol in the presence of $H_2SO_4$

When acetic acid reacts with etahnol in the presence of an acid, it leads to the formation of a fruity smelling compound known as ester which is ethyl acetate.

$CH_3COOH+CH_3CH_2OH\xrightarrow[]{H_2SO_4}CH_3COO-CH_2CH_3+H_2O$

• b. Sodium carbonate

When acetic acid reacts with sodium carbonate, it leads to the formation of sodium acetate, carbon dioxide and water.

$2CH_3COOH+Na_2CO_3\rightarrow 2CH_3COONa+CO_2+H_2O$

Answer 2

X is acetic acid or CH3COOH Acetic acid belongs to the homologous series; alkanoic acids; which are group of weak acids. They react with alkanols or alcohols to form esters or what we call alkyl alkanoates in presence of concentrated sulfuric acid. Additionally, they react with carbonates to yield a salt, water and carbon dioxide gas.
(a) Acetic acid reacts with ethanol to form ester in presence of concentrated sulphuric acid (H2SO4) CH3COOH + C2H5OH ----------------------> CH3COOC2H5 + H2O Product formed is Ethyl ethanoate or ethyl acetate.

(b) The reaction will be; Na2CO3 + 2CH3COOH ---------> 2CH3COONa + H2O + CO2 Effervescence will be observed due to the production of Carbon dioxide gas.