Final answer:
Among the compounds listed (NaI, H₂SO₄, HCl, Ba(OH)₂, KOH), H₂SO₄ (sulfuric acid) is identified as the polyprotic acid because it can donate two protons (diprotic acid), whereas the others are either monoprotic acids, bases or an ionic compound.
Step-by-step explanation:
The student has asked to identify the polyprotic acid among the given list of chemical compounds: NaI, H₂SO₄, HCl, Ba(OH)₂, and KOH.
Polyprotic acids are acids that can donate more than one proton (hydrogen ion, H+) in a water solution. The strength of a polyprotic acid decreases with each proton lost, and this is reflected in the increasing pKa with the loss of subsequent protons. Sulfuric acid, H₂SO₄, is an example of a diprotic acid because it is capable of donating two protons.
Comparing the compounds:
- NaI (sodium iodide) is not an acid, it's an ionic compound.
- H₂SO₄ (sulfuric acid) can donate two protons, making it a diprotic acid.
- HCl (hydrochloric acid) is a monoprotic acid, as it only donates one proton.
- Ba(OH)₂ (barium hydroxide) is a base, not an acid.
- KOH (potassium hydroxide) is also a base.
Therefore, among the given options, H₂SO₄ is the polyprotic acid.