Ethanol and Ethanoic Acid - Important Carbon Compounds

Carbon compounds, particularly ethanol ( $\boldsymbol{\textbf{C}_2\textbf{H}_5\textbf{OH}}$ ) and ethanoic acid ( $\boldsymbol{\textbf{CH}_3\textbf{COOH}}$ ), are crucial in both industrial and domestic applications. Ethanol is widely known for its use in alcoholic beverages, as a solvent, and as a biofuel, while ethanoic acid, also known as acetic acid, is the main component of vinegar and is used in various chemical and food industries.

Ethanol (C₂H₅OH)

Physical Properties of Ethanol:

State: Liquid at room temperature.
Boiling Point: 78°C.
Density: 0.789 g/cm³ (at 20°C).
Solubility: Ethanol is completely miscible with water and many organic solvents.
Volatility: Ethanol evaporates quickly due to its relatively low boiling point.

Chemical Properties of Ethanol:

Combustion: Ethanol undergoes combustion when exposed to oxygen, producing carbon dioxide, water, and heat energy. The reaction is highly exothermic.

$\boldsymbol{\textbf{C}_2\textbf{H}_5\textbf{OH} + 3\textbf{O}_2 \rightarrow 2\textbf{CO}_2 + 3\textbf{H}_2\textbf{O} + \textbf{Energy}}$

- Application: Ethanol is used as a biofuel in some vehicles due to its clean-burning properties, producing fewer pollutants than gasoline.

Reaction with Sodium: Ethanol reacts with sodium metal to form sodium ethoxide and hydrogen gas. This reaction demonstrates ethanol’s weakly acidic nature.

$\boldsymbol{2\textbf{C}_2\textbf{H}_5\textbf{OH} + 2\textbf{Na} \rightarrow 2\textbf{C}_2\textbf{H}_5\textbf{ONa} + \textbf{H}_2}$

Dehydration to Form Ethene: Ethanol can be dehydrated (water is removed) when heated with concentrated sulfuric acid, producing ethene ( $\boldsymbol{\textbf{C}_2\textbf{H}_4}}$ ).

$\boldsymbol{\textbf{C}_2\textbf{H}_5\textbf{OH} \xrightarrow{\text{conc.} \ \textbf{H}_2\textbf{SO}_4} \textbf{C}_2\textbf{H}_4 + \textbf{H}_2\textbf{O}}$

- Application: Ethene is a key raw material in the plastic industry, used to make polyethylene.

Real-Life Applications of Ethanol:

As a Solvent: Ethanol is used as a solvent in the manufacture of perfumes, paints, and drugs.
In Beverages: Ethanol is the active ingredient in alcoholic beverages like beer, wine, and spirits.
Disinfectant: Ethanol is a common disinfectant and is used in hand sanitizers due to its ability to kill microorganisms.

Ethanoic Acid (CH₃COOH)

Physical Properties of Ethanoic Acid:

State: Liquid at room temperature.
Boiling Point: 118°C.
Density: 1.049 g/cm³.
Solubility: Ethanoic acid is miscible with water and other organic solvents.
Odor: Pungent, vinegar-like smell.

Chemical Properties of Ethanoic Acid:

Reaction with Bases: Ethanoic acid reacts with bases (such as sodium hydroxide) to form salts (like sodium ethanoate) and water.

$\boldsymbol{\textbf{CH}_3\textbf{COOH} + \textbf{NaOH} \rightarrow \textbf{CH}_3\textbf{COONa} + \textbf{H}_2\textbf{O}}$

- Application: This neutralization reaction is widely used in industrial processes and in food preservation.

Reaction with Carbonates and Bicarbonates: Ethanoic acid reacts with carbonates (e.g., sodium carbonate) and bicarbonates (e.g., sodium bicarbonate) to produce carbon dioxide, a salt, and water.

$\boldsymbol{\textbf{CH}_3\textbf{COOH} + \textbf{NaHCO}_3 \rightarrow \textbf{CH}_3\textbf{COONa} + \textbf{CO}_2 + \textbf{H}_2\textbf{O}}$

- Application: This reaction is used in the production of baked goods, where the carbon dioxide gas helps dough rise.

Esterification: Ethanoic acid reacts with alcohols to form esters, which are sweet-smelling compounds. In the presence of concentrated sulfuric acid, ethanoic acid reacts with ethanol to form ethyl ethanoate.

$\boldsymbol{\textbf{CH}_3\textbf{COOH} + \textbf{C}_2\textbf{H}_5\textbf{OH} \xrightarrow{\textbf{H}_2\textbf{SO}_4} \textbf{CH}_3\textbf{COOC}_2\textbf{H}_5 + \textbf{H}_2\textbf{O}}$

- Application: Esters are used in the production of perfumes and food flavorings.

Real-Life Applications of Ethanoic Acid:

Vinegar: Ethanoic acid is the main ingredient in vinegar, used in cooking and food preservation.
Cleaning Agent: It is used in household cleaners to remove limescale and other mineral deposits.
Textile Industry: Ethanoic acid is used in the production of synthetic fibers, such as cellulose acetate.

Enhanced Visualizations

Chemical Structure of Ethanol ( $\boldsymbol{\textbf{C}_2\textbf{H}_5\textbf{OH}}$ )
- Ethanol is a simple alcohol with a hydroxyl group ( $\boldsymbol{-\textbf{OH}}$ ) attached to a two-carbon chain.
Chemical Structure of Ethanoic Acid ( $\boldsymbol{\textbf{CH}_3\textbf{COOH}}$ )
- Ethanoic acid contains a carboxyl group ( $\boldsymbol{-\textbf{COOH}}$ ) attached to a methyl group ( $\boldsymbol{\textbf{CH}_3}$ ).

Practice Questions with Answers

Q1: Write the balanced chemical equation for the combustion of ethanol.

Answer:

$\boldsymbol{\textbf{C}_2\textbf{H}_5\textbf{OH} + 3\textbf{O}_2 \rightarrow 2\textbf{CO}_2 + 3\textbf{H}_2\textbf{O} + \textbf{Energy}}$

Q2: How is ethanoic acid used in household cleaning products?

Answer: Ethanoic acid (as vinegar) is used in household cleaners to remove mineral deposits like limescale and to clean surfaces effectively.

Q3: Explain the esterification reaction between ethanoic acid and ethanol.

Answer: Esterification occurs when ethanoic acid reacts with ethanol in the presence of concentrated sulfuric acid, forming ethyl ethanoate (an ester) and water.

$\boldsymbol{\textbf{CH}_3\textbf{COOH} + \textbf{C}_2\textbf{H}_5\textbf{OH} \xrightarrow{\textbf{H}_2\textbf{SO}_4} \textbf{CH}_3\textbf{COOC}_2\textbf{H}_5 + \textbf{H}_2\textbf{O}}$