Which of the following mixtures would represent a proper buffer solution? A buffer solution should have approximately the same moles of a weak acid and its conjugate base (or a weak base and its conjugate acid) in a solution since the species will be at equilibrium (with Ka << 1, for instance) and the common-ion effect will be in place in order for the buffer to be effective. Group of answer choices

2.0 M hydrochloric acid & water

Sodium chloride & hydrochloric acid, 1.0 M each

Sodium sulfate & sulfuric acid, 1.0 M each

Sodium formate & formic acid, 0.1 M each

0.1 M sodium nitrate & water