1. The distillation apparatus shown in the diagram below was used to extract clove oil from cloves - Leaving Cert Chemistry - Question 1 - 2015

The part of the apparatus labelled A is called a Liebig condenser. This device is employed to cool and condense the vapors generated during the distillation process back into liquid form.

The purpose of the Liebig condenser (A) in this experiment is to cool the distillate vapours, allowing them to condense into liquid. As the vapor travels through the condenser, it loses heat, resulting in the formation of the essential oil.

The cold water should enter at Y. This ensures that the condenser is filled with cold water, allowing for efficient heat transfer and condensation of the vapors.

The appearance of the emulsion of clove oil and water collected at B is expected to be milky, white, and cloudy. This characteristic opacity arises due to the dispersion of clove oil droplets within water.

The structure of cyclohexane (C₆H₁₂) is best represented as a six-membered carbon ring, where each carbon atom is bonded to two hydrogen atoms:

       H   H
        \ / 
         C   
       /   \ 
    H-C     C-H
    |       |
   H-C     C-H
       \   /
        C
       / 
      H

This structure confirms the molecular formula of C₆H₁₂.

The organic layer in the separating funnel will be cyclohexane, which is less dense than water. Hence, cyclohexane will form the upper layer in the separating funnel.

To ensure that all of the clove oil in the emulsion ended up in the organic layer, the following steps should be taken:

1. Stopper the funnel to prevent any loss of volatile components.
2. Shake the funnel gently to mix the layers thoroughly for improved extraction of clove oil into the cyclohexane.
3. Allow the layers to separate completely after shaking.
4. Open the tap to drain the lower aqueous layer (water) while keeping the organic layer (cyclohexane with clove oil) in the funnel.

The clove oil can be isolated from the cyclohexane by using distillation techniques to evaporate the cyclohexane. This can be achieved through:

• Heating the mixture to boil off cyclohexane.
• Implementing a water bath or hotplate to control the temperature and avoid high heat that could degrade the clove oil. After the cyclohexane evaporates, the clove oil will remain as a residue.