Consider this equilibrium for a buffer solution: ch3cooh + h2o ch3coo- + h3o + . when a small amount of acid is added to this system, which statement is true when equilibrium is reestablished? a. [ch3coo-] and ph have both increased. b. [ch3cooh] and ph have both decreased. c. [ch3coo-] has decreased and ph remains relatively constant. d. [ch3cooh] has decreased and ph remains relatively constant. e. [ch3coo-] has increased and ph remains relatively constant.