You are tasked with creating 0.500 L of a buffer using the least amount of reagents.
- It must have a pH of 4.30
You may choose from the following:

Hydrocyanic acid = HCN, pKa = 9.21 (with sodium cyanide, NaCN)

Hydrazidic acid=HN3, pK=4.72 (with sodium azide,NaN₁)

Formic Acid=HCHO₂, pK=3.74 (with sodium formate, NaCHO₂)

Hydrofluoric acid = HF, PK,- 3.20 (with sodium fluoride, NaF)

A. Choose your buffer system, justify your selection.