Lead piping for potable water is unsafe because dissolved oxygen attacks Pb to form toxic Pb(OH)2. Which reagent readily corrodes lead pipes, accelerating contamination risk?

Introduction / Context:
Material compatibility with drinking water systems is a public health issue. Lead can leach into water forming soluble or weakly adherent corrosion products; organic acids aggravate attack, raising toxicity risks.

Given Data / Assumptions:

• Lead metal in contact with slightly acidic, oxygenated water.
• Common corrosives considered: mineral acids and organic acids.

Concept / Approach:
Lead exhibits complex corrosion behavior. It can form protective films (e.g., PbSO4 in concentrated sulfuric acid) or sparingly soluble salts (e.g., PbCl2) that slow attack in some environments. Acetic acid, however, forms soluble lead acetate species, increasing corrosion rate and lead dissolution into water.

Step-by-Step Solution:
1) Evaluate HCl: PbCl2 is sparingly soluble; a passivating film may form, reducing sustained attack.2) Evaluate concentrated H2SO4: formation of PbSO4 film strongly inhibits further corrosion.3) Evaluate acetic acid: forms soluble acetate complexes; corrosion continues and lead can leach.4) Conclude acetic acid most readily corrodes lead piping in potable contexts.

Verification / Alternative check:
Plumbing corrosion studies and historical incidents emphasize organic acids (including acetate) increasing Pb solubility, consistent with the chemistry of lead acetate formation.

Why Other Options Are Wrong:
Dilute HCl: some attack occurs but often limited by PbCl2 film.
Concentrated H2SO4: strong passivation; low continuous attack.
None of these: incorrect because acetic acid is clearly aggressive.
Dilute HNO3 (not chosen in options originally but noted): typically oxidizes lead, but the question targets common potable-water organics.

Common Pitfalls:
Assuming all strong acids are more corrosive without considering passivation or solubility of corrosion products.

Final Answer:
acetic acid (CH3COOH)