Study Notes
Alcohols are organic compounds with the general formula CnH2n+1OH and contain the hydroxyl (-OH) functional group. Ethanol can be produced by fermentation of glucose or by the hydration of ethene, and it is used as a solvent and a fuel.
- Fermentation — a biological process to produce ethanol using glucose and yeast in the absence of oxygen. Example: Glucose is converted to ethanol and carbon dioxide at around 30°C.
- Hydration of Ethene — a chemical process where ethene reacts with steam to produce ethanol. Example: Ethene and steam react in the presence of a phosphoric acid catalyst at 300°C and 60-70 atm.
- Combustion of Ethanol — a reaction where ethanol burns in oxygen to produce carbon dioxide and water. Example: CH3CH2OH + 3O2 → 2CO2 + 3H2O.
Exam Tips
Key Definitions to Remember
- Alcohols: Organic compounds with the general formula CnH2n+1OH.
- Fermentation: Biological process to produce ethanol using glucose and yeast.
- Hydration of Ethene: Chemical process where ethene reacts with steam to produce ethanol.
Common Confusions
- Confusing fermentation with hydration as both produce ethanol but have different conditions.
- Misunderstanding the role of catalysts in the hydration process.
Typical Exam Questions
- What are the conditions required for fermentation? Yeast, absence of oxygen, and temperature around 30°C.
- How is ethanol produced from ethene? By reacting ethene with steam in the presence of a phosphoric acid catalyst at high temperature and pressure.
- What are the products of ethanol combustion? Carbon dioxide and water.
What Examiners Usually Test
- Understanding of the conditions and processes for ethanol production.
- Ability to write balanced chemical equations for reactions involving alcohols.
- Knowledge of the uses and properties of ethanol.