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Alcohols and Carboxylic Acids

Alcohols and Carboxylic Acids

Alcohols

Alcohols are a group of compounds that have a hydrocarbon chain attached to an -O-H group. The general formula for an alcohol is 

Alcohols and Carboxylic Acids, figure 2

The___ -O-H___ part is what makes it an alcohol!

Properties of alcohols

  1. Flammable
  2. The first four (so methanol, ethanol, propanol and butanol) alcohols dissolve completely in water to make a neutral solution.
  3. They react with sodium
  4. They form carboxylic acids when they react with oxygen (from the air). More on carboxylic acids later.
Alcohols and Carboxylic Acids, figure 3

Uses of Alcohols

__Alcohols have many uses: __

  1. Alcoholic drinks – Ethanol is mainly used. Methanol can blind you if drank. Alcohol poisons the body, which makes people ‘drunk’.
  2. Solvents – alcohols can dissolve most substances that water can dissolve and more.
  3. __Fuels __– since alcohol is flammable, it can be burnt with air which releases energy.

Making ethanol from sugars

Yeast turns sugar into carbon dioxide and ethanol. This is one of the main ways that ethanol is produced industrially. This is called fermentation.

Alcohols and Carboxylic Acids, figure 1

In lots of alcoholic drinks, the alcohol isn’t added but it’s made in the liquid by adding yeast. The yeast turns the sugar into carbon dioxide gas and ethanol!

Carboxylic Acids

Carboxylic acids have a -COOH group added to the hydrocarbon chain. These are named the same way as alkanes and alkenes, except we write ‘-anoic acid’ at the end instead of -ene or -ane.

Alcohols and Carboxylic Acids, figure 1

Properties of Carboxylic Acids

Properties of carboxylic acids

  1. They react like acids (for example, they neutralise bases)
  2. Dissolve in water
  3. They are weak acids – they only partially ionize in water (see #StrongAndWeakAcids2 section).
  4. They can react with alcohols to form esters

Esters

Esters are formed when an alcohol reacts with a carboxylic acid.

Alcohols and Carboxylic Acids, figure 1