Question

An organic compound is widely used as a preservative in pickles and has a molecular formula , ${C_2}{H_4}{O_2}$ the compound reacts with ethanol to form a sweet smelling compound $B$.
1.Identify the compound $A$.
2.Write chemical equation for its reaction with ethanol to form compound $B$.
3.How can we get compound $A$ back from $B$ ?
4.Name the process and write its chemical equation.
5.Which gas is produced when compound $A$ reacts with washing soda?

Answer 1

This question gives the knowledge about chemical formulas of organic compounds and saponification or the hydrolysis of the ester. The hydrolysis of ester results in breaking of an ester bond due to hydroxide ion or a water molecule to form an alcohol and a carboxylic acid.

Complete step by step solution:
Organic compounds are the compounds that contain carbon and hydrogen bonds.
$1$. An organic compound which is widely used as a preservative in pickles having molecular formula ${C_2}{H_4}{O_2}$ is ethanoic acid. Therefore, the compound $A$ is acetic acid. The molecular formula of acetic acid is $C{H_3}COOH$. It is a weak acid and is very essential for human beings as it reduces inflammations and lowers the blood pressure. Acetic acid is also known as vinegar.
$2$. When acetic acid reacts with ethanol it leads to the formation of ethyl acetate and water. The chemical equation for the reaction to obtain compound $B$ is as follows:
$C{H_3}COOH + {C_2}{H_5}OH \to C{H_3}COO{C_2}{H_5} + {H_2}O$
Where $C{H_3}COOH$ is acetic acid, ${C_2}{H_5}OH$ is ethanol, $C{H_3}COO{C_2}{H_5}$ is ethyl acetate and ${H_2}O$ is water.
$3$.The process required to obtain compound $A$ back from compound $B$ is hydrolysis of ester. The hydrolysis of ester results in breaking of an ester bond due to hydroxide ion or a water molecule to form an alcohol and a carboxylic acid. . The hydrolysis is carried out in the presence of an acid or a base. Here dilute $HCl$ is used as a catalyst to carry out the ester hydrolysis.
$4$. The process used is saponification. The saponification is the process that leads to the conversion of fat or a lipid into alcohol and soaps in the presence of alkali. The chemical equation for the following reaction is:
$C{H_3}COO{C_2}{H_5} + {H_2}O \to C{H_3}COOH + {C_2}{H_5}OH$
$5$. $C{O_2}$ Gas is evolved when compound $A$ reacts with washing soda. The chemical equation for this reaction is as follows:
$C{H_3}COOH + NaHC{O_3} \to C{H_3}COONa + C{O_2} + {H_2}O$
Where $C{H_3}COOH$ is acetic acid, $NaHC{O_3}$ is washing soda, $C{H_3}COONa$ is sodium acetate and $C{O_2}$ is carbon dioxide.

Note: You should have the complete knowledge about the chemical formulas of the organic compounds. And always remember in hydrolysis of ester, ester bond breaks due to the action of water molecules only.