Which of these elements is unlikely to have a reaction with any element or compound? a. rubidium (rb) b. magnesium (mg) c. cobalt (co) d. argon (ar)

Which statement is true about a catalyst? a: a catalyst decreases the rate of the reaction. b. a catalyst is consumed during a chemical reaction. c. a catalyst lowers the activation energy of a reaction. d. a catalyst increases the reactant concentration during a reaction.