Answer:
D- Assertion is false and Reason is true
Explanation:
Precipitation is said to have occurred when an insoluble product is formed from soluble ones. Let us take an instance;
BaCl2(aq) + H2SO4(aq) -------> BaSO4(s) + 2HCl(aq)
The barium sulphate so formed is an insoluble product obtained from the reaction of soluble barium chloride and sulphuric acid. This is a typical example of a double replacement reaction as the both ions exchanged partners.
Thus, the assertion is false but the reason is true.