How would you prepare 0.5 ml of a 0.5mol / L benzoate buffer at pH 4.5 using a 4.0mol / L benzoic acid solution and a 2.0mol, d * m ^ - 3 sodium benzoate solution? The pKa value of benzoic acid is 4.19.

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.