Concentrated acids and alkalis are usually corrosive.

Concentrated Hydrochloride Acid

  Has a concentration of about 11M which contains 35% hydrogen chloride by mass. A volatile colorless liquid that gives out acid mist and a strong smell in air. It attacks skin and eyes. Its corrosive is due to its high concentration of hydrogen ions.

Concentrated Nitric Acid

  Concentrated nitric acid(about 16M) contains about 70% nitric acid by mass. It is a volatile colorless liquid that gives out acid mist and a strong smell in air. It often turns yellow on storage. It attacks the skin very readily and stains it yellow. Its corrosive nature is due to its oxidizing property.

This is the reason why concentrated nitric acid is usually stored in a brown bottle

Concentrated Sulphuric Acid

  Concentrated sulphuric acid(about 18M) contains about 98% sulphuric acid by mass. It is a colorless oily liquid which is non-volatile, so it does not give an acid mist when exposed to air. It concentrated sulphuric acid quickly dehydrates the skin upon contact, causing serve burns. Its corrosive nature is due to its oxidizing and dehydrating properties.

Concentrated Alkalis

  Concentrated sodium hydroxide and potassium hydroxide solutions are very corrosive especially when they are hot. They attack the skin readily and stain it yellow or even black. Their corrosive nature is due to their high concentration of hydroxide ions.

Safety Precautions in Handling Concentrated Acids and Alkalis

1. Wear protective gloves and safety spectacles

2. Perform the experiments in fume cupboards ti avoid breathing in any acid mist

3. In diluting concentrated acids or alkalis, add them slowly to a large amount of water with stirring