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Use the weak-acid mode.","exampleUseCases":[{"title":"Buffer pH for lab protocol","prompt":"I'm preparing a phosphate buffer for a biology experiment. The pKa is 7.2, the weak-acid concentration is 0.08 M, and the conjugate-base concentration is 0.12 M. What pH will that buffer have?"},{"title":"Strong acid pH for chemistry homework","prompt":"What are the pH and pOH of a 0.002 M solution of hydrochloric acid? It's a strong acid that releases one proton per molecule."},{"title":"Hydrogen-ion concentration from pH","prompt":"If a solution has a pH of 3.7, what is the hydrogen-ion molar concentration and the corresponding pOH?"}],"resultDescription":"Returns pH (numeric), pOH (numeric), hydrogen-ion molarity, hydroxide-ion molarity, percent ionized (for weak acids/bases), the mode used, a plain-language summary, and an optional disclaimer — all as a JSON object.","failureModes":["Missing required 'mode' parameter returns an error","Providing an invalid mode string returns a validation error","Supplying concentration or Ka/Kb of zero or negative numbers may produce NaN or error responses","Omitting Ka/Kb for weak-acid/weak-base mode causes calculation failure","Omitting acidConc or baseConc for buffer mode causes failure","Network or payment errors may prevent the call from completing"],"whenToPreferThis":"Choose this endpoint when you need precise, formula-based acid-base pH/pOH calculations across all common chemistry scenarios — strong acids, strong bases, weak acids, weak bases, buffers, or pH/[H⁺] interconversions — and want a single API that handles all modes. Prefer it over general-purpose LLM math for accuracy and over building your own logic for breadth of coverage.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-29T13:14:25.400Z","isFirstParty":false,"canonicalSlug":"chemistry-calculators-ph-poh-calculator-8a325648"}