Question

Which of the following is NOT laboratory evidence of a chemical reaction?

A. Large chunks of sodium chloride are placed in a mortar and pestle. The sodium chloride is broken into smaller pieces.

B. Hydrochloric acid is poured in a test tube containing a piece of magnesium. Bubbles of gas form.

C. A solution of silver nitrate is added to a solution of sodium chloride. A solid white substance forms.

D. A solution of sodium sulfide is added to hydroiodic acid. A rotten smell is given off.

Answer 1

B! the answer is B. bubbles of gas form

Answer 2

A. Large chunks of sodium chloride are placed in a mortar and pestle. The sodium chloride is broken into smaller pieces.

Step-by-step explanation:

This is an example of physical change where the physical properties of the substance are altered without any formation of a new substance. So, it is not an evidence of a chemical reaction.