Nomenclature of phosphoric acids – identify H3PO4 H3PO4 corresponds to which commonly named phosphoric acid type in inorganic chemistry?

Introduction / Context:
Phosphorus oxyacids appear in several forms. Recognizing their empirical formulas and conventional names is important for fertilizer chemistry, water treatment, and analytical reagents.

Given Data / Assumptions:

• Orthophosphoric acid: H3PO4, the simplest triprotic acid of phosphorus.
• Pyrophosphoric acid: H4P2O7, a condensed dimer.
• Metaphosphoric acids: general formula (HPO3)n, polymeric rings or chains.

Concept / Approach:
H3PO4 is the monomeric, fully hydrated form known as orthophosphoric acid. Condensation of two orthophosphoric molecules removes water to form pyrophosphoric acid. Further condensation produces metaphosphoric (polymeric) forms. Therefore, H3PO4 must be orthophosphoric acid in standard nomenclature.

Step-by-Step Solution:

Verification / Alternative check:
Chemical handbooks universally list H3PO4 as orthophosphoric acid, used widely in fertilizers and food-grade acids.

Why Other Options Are Wrong:

• Pyro: H4P2O7, not H3PO4.
• Meta: (HPO3)n, different stoichiometry.
• None: Incorrect because a correct match exists.

Common Pitfalls:
Mixing up the “ortho,” “pyro,” and “meta” prefixes; remember that condensation increases P:O ratio complexity and changes hydrogen count.

Final Answer:
orthophosphoric acid