Question

Which of these is an indication that a chemical reaction has occurred?

A.melting of a substance

B.boiling of a substance

C.formation of a precipitate

D.freezing of a substance

Answer 1

C. Formation of a precipitate.

Answer 2

• 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