Question

What is fermentation? How is Ethanol prepared by fermentation? Give any two uses of ethanol?

Answer 1

Part 1:

The larger molecules decomposes slowly by the action of enzymes. This process is known as Fermentation.

Part 2:

Preparation of Ethanol:

1. Molasses is a source of Sugar. In the commercial preparation of Ethanol, sugar is fermented.
2. In the process of fermentation, molasses is diluted to three times by adding water.
3. $$\begin{gathered} {\mathrm{C}}_{12}{\mathrm{H}}_{22}{\mathrm{O}}_{11}\left(\mathrm{s}\right)+{\mathrm{H}}_2\mathrm{O}\left(l\right)\underset{}{\overset{\mathrm{Invertase}}{\to }}{\mathrm{C}}_6{\mathrm{H}}_{12}{\mathrm{O}}_6\left(\mathrm{aq}\right)+{\mathrm{C}}_6{\mathrm{H}}_{12}{\mathrm{O}}_6\left(\mathrm{aq}\right) \\ \mathrm{Sucrose}\mathrm{Glucose}\mathrm{Fructose} \\ \left(\mathrm{Molasses}\right) \end{gathered}$$
4. Sugar undergoes fermentation in presence of Zymase (enzyme) to form Ethanol and Carbon dioxide.
5. The chemical reaction is,
6. $$\begin{gathered} {\mathrm{C}}_6{\mathrm{H}}_{12}{\mathrm{O}}_6\left(\mathrm{s}\right)\underset{}{\overset{Zymase}{\to }}2{\mathrm{C}}_2{\mathrm{H}}_5\mathrm{OH}\left(\mathrm{l}\right)+2{\mathrm{CO}}_2\left(\mathrm{g}\right) \\ \mathrm{Glucose}\mathrm{Ethanol}\mathrm{Carbon}\mathrm{dioxide} \end{gathered}$$

Part 3:

Uses of Ethanol:

1. It is used as a fuel substituent in the internal combustion of engines of cars and scooters.
2. It is used as a preservative for biological specimens.