Describe how ethanol is produced from sugar solution. Give the name of this process.
How to approach this question
1. **Name:** Recall the biological process used to make alcohol from sugar, often used in brewing and baking.
2. **Description:** What microorganism is needed for this process? What are the ideal conditions (temperature, oxygen levels)? What are the products of the reaction?
Full Answer
The production of ethanol from a sugar solution is a biological process called **fermentation**.
The key steps are:
1. **Yeast** is added to a solution of sugar (like glucose). Yeast is a microorganism that contains enzymes (such as zymase).
2. The mixture is kept in **warm conditions**, typically between 25°C and 40°C. This is the optimal temperature for the yeast's enzymes to work efficiently. If it's too cold, the reaction is too slow; if it's too hot, the enzymes denature.
3. The reaction must be carried out in the **absence of oxygen** (anaerobic conditions). If oxygen is present, the yeast will respire aerobically, producing carbon dioxide and water instead of ethanol.
The overall equation for fermentation is:
Sugar (glucose) → Ethanol + Carbon dioxide
Common mistakes
✗ Forgetting to mention yeast.
✗ Forgetting the specific conditions (warm, anaerobic).
✗ Confusing fermentation with other processes like distillation.
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