Oxidation/reduction (redox) reactions like this: 2h2(g) + o2(g) ⇒ 2h2o(l) will occur spontaneously. to make the reaction proceed in the reverse direction, you must put energy (electricity) into reaction. this is called

Two solids are mixed in a flask and stirred. after a few minutes, the flask becomes cold. which of the following best describes this reaction? a. an exothermic reaction b. a combustion reaction c. an endothermic reaction d. a decomposition reaction