Question

give an example for each type of the following types of double displacement reaction :
a)when precipitate is formed
b)when a change of colour is observed
c)when a gas is formed

Answer 1

When a precipitate is formed,
KI+Pb(NO3)2----◆PbI2+KNO3
...........
Precipitate.
When change in colour ,
Above reaction also change in colour
Lead iodide is yellow in colour which is obtained from colourless lead nitrate.
When a gas is formed,
Ba(OH)2+NH4CI---◆BaCl+NH3+H20.
We know that ammonia is a gas.