Answer:
- The correct option is C.
- Formation of a precipitate
Step-by-step explanation:
During a chemical reaction, new substances are formed known as a products, mostly reaction occur and their product is obtained as precipitates.
Example
Arylidene-2-thiobarbituric acid is obtained as precipitates when aldehyde and thiobarbituric acid react to each other.
melting of a substance
It is just indication of physical changes, like melting of ice, composition remained same as before.
boiling of a substance
It is just indication of physical changes, like boiling of water into vapors, composition remained same as before.
freezing of a substance
It is just indication of physical changes, like freezing of water into ice, composition remained same as before