Choose the following statements that show evidence for a chemical reaction.
1. dropping sodium metal into water produces fizzing
2. dissolving a white powder in solution gives white light
3. mixing two aqueous solutions produces a precipitate
4. mixing two 10.0 ml solutions gives a volume of 19.5 ml

Explanation:

A chemical reaction is defined as the reaction in which bonds between the reactants either break or form which leads to the formation of a new substance.

For example,

So, when we drop a sodium metal into water then it produces a frizzing sound which shows the metal is reacting with water.

We know that when two aqueous solutions chemically react with each other then it may lead to the formation of an insoluble substance which is known as precipitate.

This means that formation of a precipitate is also a chemical reaction.

Thus, we can conclude that following are the statements which show evidence for a chemical reaction.

atomic number of carbon is 6

electronic configuration of carbon is 1s²2s²2p²

orbital diagram of c is as shown here in the image.