An experiment must be carried out at pH 9.0

CHEMISTRY · Subjective · A Level · Chemistry · Acids and bases · Acids and bases

Problem

An experiment must be carried out at pH 9.0. Three weak acid–base conjugate pairs are available: • formic acid/formate (

pK_a = 3.75

) • ammonium ion/ammonia (

pK_a = 9.25

) • acetic acid/acetate (

pK_a = 4.76

) Identify the pair that would provide the most suitable buffer at the required pH and give one brief reason for your choice.