Why is the Earth wire so very important in any electrical appliance?

The Earth wire is very important in any electrical appliance because if the appliance develops a fault, the fault current is safely discharged through the plug to the ground. This protects the appliance user from electrical shock or damage.

Alcohols and Carboxylic acids both have hydrogen bond as inter-molecular forces. Explain why Carboxylic acids evaporate at higher temperatures than alcohols.

The carboxylic acid molecule has two sites of hydrogen bonding and alcohol molecule has one site of hydrogen bonding. This means carboxylic acids require more energy to separate the bonded molecules (because of two hydrogen bonding sites) and alcohols require less energy to separate the molecules (because of one hydrogen bonding site)

Define the term weak Acid

A weak acid is a substance that partially ionizes. A good example is ethanoic acid which will have both ethanoic acid molecules and ethanoate ions and protons at the end showing that it did not completely ionize.