Which of the following mixtures would represent a proper buffer solution? Think about this: Strong acids and strong bases alone can never be used as a buffer solution because common ion effect does not apply to them. A mixture of a weak acid (or a weak base) and its conjugate gives the best buffer because common ion effect would apply. A mixture of two unrelated species (such as NaCl and KBr) where neither is particularly acidic or basic cannot be counted as a buffer. Neutral solutions or water is not a buffer. A strong acid (or a strong base) mixed together with its conjugate (e. g., Cl– with HCl) is not a buffer. A. Sodium chloride & hydrochloric acid

B. Hydrochloric acid & water

C. Sodium formate & formic acid

D. Sodium nitrate & water

E. Sodium sulfate & sulfuric acid