Chemistry

General Properties of Acids :
1. They are sour in taste.
2. They turn blue litmus paper red.
3. Acids show acidic properties only in the presence of water. This can be demonstrated by the following activity.
Dry hydrogen chloride gas does not produce H⁺ ions in the absence of moisture/water. It produces H⁺ ions only in the presence of moisture/water.
HCl + H₂O → H₃O⁺ + Cl^–
4. Their aqueous solutions conduct electricity.
5. They react with certain metals with the evolution of hydrogen gas.
EXAMPLES :
Metals like potassium, sodium, calcium, magnesium, aluminium, zinc and iron can react with the aqueous solution of an acid to evolve hydrogen gas.




These reactions show certain metals can displace hydrogen from acids to form salts.
Nitric acid reacts only with magnesium and manganese. In both the reactions hydrogen gas is evolved.


Nitric acid does not behave like this with any other metal.
6. They can react with bases to produce salts and water. [We will study these reactions when we deal with the bases.]
7. They react with carbonates and hydrogencarbonates to form carbon dioxide and a salt.

This activity may be used as a method of determining if a given substance is an acid or not.