alcohols

What happens when alcohols burn in oxygen?

They burn very well with oxygen to produce carbon dioxide and water.

What happens when alcohols react slowly with oxygen?

They are oxidised to carboxylic acids by mild oxidising agents.

What is the mild oxidising agent used in the lab to oxidise alcohols?

Acidified potassium dichromate.

What colour change occurs when acidified potassium dichromate is used as an oxidising agent?

It changes from orange to green as it dumps its oxygen.

What is the name of the process used when oxidising ethanol in the lab?

Reflux.

Why must the Liebig condenser have an open top during reflux?

To prevent pressure build-up and explosion.

What are the two main methods of making ethanol?

Fermentation and hydration of ethene (ethene + steam).

What are the conditions for producing ethanol from ethene and steam?

Temperature: 300°C; Pressure: 60–70 atmospheres; Catalyst: phosphoric acid (H₃PO₄).

What are the pros of making ethanol from ethene and steam?

Continuous and fast process; produces pure ethanol.

What are the cons of making ethanol from ethene and steam?

Uses fossil fuels, which are finite resources.

What materials and conditions are needed for fermentation to produce ethanol?

Sugar (e.g. glucose), water, yeast, 30–40°C, absence of oxygen.

Why must fermentation take place without oxygen?

To prevent oxidation of ethanol into ethanoic acid (vinegar).

What are the pros of making ethanol by fermentation?

Renewable process; uses crops instead of fossil fuels.

What are the cons of making ethanol by fermentation?

Slow and non-continuous process; ethanol produced is impure and must be distilled.

What does ethanol oxidise into when exposed to air over time?

Ethanoic acid (vinegar) – a process called microbial oxidation.

What is the functional group in alcohols?

The hydroxyl group (-OH).

What is the displayed formula for ethanol (C₂H₅OH)?

H–C–C–O–H (with hydrogens filling remaining bonds).

What family of compounds do methanol, ethanol, propanol, and butanol belong to?

The alcohol homologous series.

What is the molecular formula and name for methanol?

CH₄O – Methanol.

What is the molecular formula and name for ethanol?

C₂H₆O – Ethanol.

What is the molecular formula and name for propanol?

C₃H₈O – Propanol.

What is the molecular formula and name for butanol?

C₄H₁₀O – Butanol.