A chemist added hydrochloric acid to a sample of baking soda in a beaker. Immediately, the mixture of the two chemicals began to fizz and bubble. Which
of the following observations about the fizzing mixture provides evidence of a
chemical reaction?

a patient chooses to not take a beneficial medical treatment.

explanation:

a). in this case, dh> 0 and sd> 0. if t becomes larger, the term "-tds" will become more negative. at some point, it is possible that -dts will be more negative than the dh is positive, and the reaction will become spontaneous. this is probably the correct answer, but you should look at all of the other possibilities and make sure of that.