State the uses of ethanol as: (a) a solvent (b) a fuel

Organic Chemistry – Alcohols

Uses of Ethanol as a Solvent

Ethanol, written as \$C2H5OH\$, is a versatile solvent. Think of it as a “mix‑and‑match” friend that can dissolve many different substances, just like a good friend who can chat with anyone at a party. It is especially useful in chemistry labs because it is:

  • Non‑toxic and relatively safe to handle.

  • Highly polar, so it can dissolve both polar and some non‑polar compounds.

  • Easy to evaporate, leaving behind the dissolved substance.

  • Compatible with many common laboratory glassware and equipment.

Exam Tip: Remember that ethanol is a secondary alcohol and can act as a good solvent for reactions that require a polar, protic environment. In multiple‑choice questions, look for clues like “polar protic solvent” to pick ethanol.

Uses of Ethanol as a Fuel

Ethanol can also power engines, similar to how a car’s battery powers its lights. When burned, it releases energy that can be harnessed to move a vehicle. Key points:

  1. Combustion reaction: \$C2H5OH + 3O2 \rightarrow 2CO2 + 3H_2O\$

  2. Produces less carbon monoxide (\$CO\$) compared to gasoline, making it cleaner.

  3. Can be blended with gasoline (e.g., E10, E85) to reduce fossil fuel use.

  4. Renewable source: produced from plant sugars, so it’s a green fuel.

Exam Tip: When asked about ethanol as a fuel, recall the combustion equation and the environmental benefit of lower \$CO\$ emissions. Also, note that ethanol’s energy density is about 70% that of gasoline.

ApplicationKey FeatureExam Hint
Solvent in labsPolar protic, easy evaporationLook for “polar protic solvent”
Fuel (E10, E85)Lower CO emissions, renewableRecall combustion equation and energy density

Quick Recap: Ethanol is a friendly solvent that helps scientists mix and study chemicals, and it’s also a cleaner fuel that can power cars while reducing pollution. Keep these two roles in mind when you tackle exam questions about alcohols! 🚗💧