What do you mean by a precipitation reaction? Explain by giving examples.
Answer:
A reaction in which an insoluble solid (called precipitate) is formed is called a precipitation reaction.
Example 1:
CaCl2 (aq) + Na2CO3 (aq) → CaCO3 (s) + 2 NaCl (aq)
In this reaction, calcium carbonate (CaCO3) is obtained as a precipitate. Hence, it is a precipitation reaction.
Example 2:
BaCl2 (aq) + Na2SO4 (aq) → BaSO4 (s) + 2 NaCl (aq)
In this reaction, barium sulphate (BaSO4) is obtained as a precipitate.