Section D: Give a long answer to the question given below.
34.B.iii. What happens when ethanol is heated at \(443K\) in the presence of conc. \(H_2SO_4\)? Write the role of conc. \(H_2SO_4\) in this case.
iv. Write an equation showing saponification.
iv. Write an equation showing saponification.
iii. When ethanol is heated at 443K (170°C) in the presence of concentrated sulfuric acid, it undergoes a dehydration reaction to form ethene (ethylene). The concentrated sulfuric acid acts as a , removing a water molecule from ethanol.
The balanced chemical equation for this reaction is:
\(C_2H_5OH\) \(\xrightarrow[H_2SO_4]{443K}\) \(C_2H_4\) + \(H_2O\)
The role of concentrated sulfuric acid in this reaction is to facilitate the removal of a molecule from ethanol to produce ethene.
iv. Saponification is the process of making soap from fats or oils and an alkali. It involves the of triglycerides (fats/oils) by a strong base, such as sodium hydroxide, resulting in the formation of glycerol and soap (sodium salt of fatty acid).
The general equation for the saponification reaction is:
Fat/Oil (Triglyceride) + sodium hydroxide → Glycerol + Soap (Sodium salt of fatty acid)
For example, the saponification of glyceryl tripalmitate (a triglyceride) with sodium hydroxide can be represented as:
\(C_3H_5(OOCC_1{_5}H_3{_1})_3\) + \(3NaOH\) → \(C_3H_5(OH)_3\) + \(3C_1{_5}H_3{_1}COONa\)
Here, glyceryl tripalmitate reacts with sodium hydroxide to produce glycerol and sodium palmitate (a type of soap).