Josh decided to mix some vinegar with baking soda. He knew that a reaction occurred because he made careful observations. He noted that the mixture started to foam up and bubble and was white in color

Josh decided to mix some vinegar with baking soda. He knew that a reaction occurred because he made careful observations. He noted that the mixture started to foam up and bubble and was white in color. How did Josh know that a chemical reaction occured? He was sure a reaction occurred because of

A) the formation of a gas.

B) the color of the mixture.

C) the smell of the vinegar.

D) the volume of the mixture.