Question

Write the structural formula of ethanol. What happens is it heated with excess of conc.${H_2}S{O_4}$ acid at $443k$? Write the chemical equation for the reaction, stating the role of conc.${H_2}S{O_4}$ acid in this reaction.

Answer 1

We need to know that the molecular formula of ethyl alcohol is ${\text{C}}{{\text{H}}_{\text{3}}}{\text{C}}{{\text{H}}_{\text{2}}}{\text{OH}}$. The molecular weight of ethyl alcohol is ${\text{46g}}$. Alcohol is the functional group present in ethyl alcohol. The molecular formula of ethylene is ${\text{C}}{{\text{H}}_2}{\text{ = C}}{{\text{H}}_{\text{2}}}$. The molecular weight of ethylene is ${\text{18g}}$.

Complete answer:
We can draw the structural formula of ethanol is below,

When ethanol is heated with excess of conc.${H_2}S{O_4}$ acid at $443k$ to give a product of ethylene.
The chemical equation for the above discussion is given below,
$C{H_3}C{H_2}OH + {H_2}S{O_4} \to {\text{C}}{{\text{H}}_2}{\text{ = C}}{{\text{H}}_{\text{2}}}$
The reaction is given below,

The role of conc.${H_2}S{O_4}$ acid in this reaction is a dehydrating agent.

Note:
In organic chemistry oxidation and reduction are important concepts. The oxidation and reduction are used to convert one functional group of molecules to another functional group. One homologous form to another homologous form of hydrocarbon is also possible in oxidation and reduction reaction. In one reaction oxidation followed by reduction reaction or the reduction reaction followed by oxidation reaction is called redox reaction. The oxidation reaction means the addition of oxygen or the removal of hydrogen or the loss of electrons in the reaction from reactant to product. The reduction reaction means the addition of hydrogen or the removal of oxygen or gain of electrons in the reaction from reactant to product.
So, first ethylene is treated with sulphuric acid to form sulfonium intermediate and followed by hydrolysis done means we get ethyl alcohol as a product.
Ethyl alcohol is industrially prepared from ethylene by absorbing in ${{\text{H}}_{\text{2}}}{\text{S}}{{\text{O}}_{\text{4}}}$ followed by hydrolysis.