How can you tell if an element has been reduced? O A. The number of its electrons has not changed in the reaction.
B. It has more electrons in the product than in the reactant.
O C. It has fewer electrons in the product than in the reactant
D. It has a positive oxidation state in the product.

answer: c. the experiment shows that the red substance experienced a chemical change.

explanation: chemical change is the change in which chemical composition of the substance changes. physical change is the change in which there is no change in chemical composition.

chemical changes are accompanied by following changes:

a) precipitate formation

b) energy is released or absorbed

c) formation of bubbles

d) change in color

as it is given that the red color has disappeared and there is production of gas, it means the red substance has undergone a chemical change.

e