chemistry.acid_base.ph

Three distinct suites: educational examples on the calculator page, this legacy regression count (14/14 golden + boundary), and the CVP verification suite below. They are not the same number. Property, metamorphic, round-trip, O3, and interface statuses/checks are recorded in the CVP Manifest . SKIP (0/0) means that suite has no published vectors.

This calculator CURRENT · Public schema 1.0.1 matches · Semantic contract ✓ · Production attested · Public/cache ✓ · Origin ✓

CVP verification suite

Protocol checks from the Evidence Manifest. Distinct from the legacy regression suite above. Verification revision 2026-09-25.o2-o3.2. Calculation version 1.0.1. CVP 1.0.0-proposed. 4/4 golden · 6/6 CVP boundary · 5/5 invalid · 1/1 property · 1/1 metamorphic · 8/8 O3 · 2/2 cross-interface · 5/5 CVP contract. digest 82c9acd33c3c. O2: water ion product at 25 °C vs a separate-module identity (≤2 ULP). Not a buffer. ≤2 ULP vs O3 applies only to the published tabulated pH vectors. Not a buffer.

• Golden (oracle-backed) 4 / 4
• CVP boundary 6 / 6
• Invalid input 5 / 5
• Property 1 / 1
• Metamorphic 1 / 1
• O3 high-precision 8 / 8
• Cross-interface 2 / 2
• CVP contract 5 / 5
• Interfaces PASS · UI (SSR) / REST / MCP
• Interface claim ui-ssr is query-result HTML, not a live browser session. Error-path engine·REST·MCP 1/1 (status, code, calculation_version). SSR compared on URL-canonical requested calculations; empty query is idle (not an error) and JSON-typed object/array inputs are REST/MCP-only.
• Verified scope pH = −log10(h) and pH + pOH = 14 at 25 °C, + O3 mpmath tabulated pH.
• Assurance Engineering
• Deferred Not a buffer and not an activity-based pH.

• release artifacts aligned PASS
• schema output required declared PASS
• schema valid input executes PASS
• engine success output validates schema PASS
• rest success payload validates schema PASS

Fingerprint sha256:04cec5f6c1592ba73b3b5e2a050de92b09b342b1a78b6a5dc9e80f5eb82ca302

Input schema sha256:8a616520a7c1716956418626fe11dc5ef7a38e3d4a69ad59f6be891179d3b2f8 · Output schema sha256:04ab729484e355638be8ebb990d46f82988bf6794b5a72320a0176784bb2a9e1 · Build-time SHA-256 digests prove published artifacts agree with each other (release_integrity.scope=workspace). Production attestation GETs canonical URLs twice (public/cached view and origin), including Capability HTML, via npm run attest:production --write (published at /.well-known/calculatorx-production-attestation.json) and fails if the public Capability page advertises a different calculation_version. This is artifact consistency, not an independent immutable release log.

Tool

ph

Engine

ph

Engine build

2026-09-25

Evidence core

2026-09-25T00:30:32.689Z

Rendered

2026-10-23T01:27:11.353Z

Last reviewed

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Assumptions

• pH = −log10[H+]
• pOH = −log10[OH−]
• Kw = 1e-14 at 25 °C
• Not Henderson–Hasselbalch
• Not ICE or activity coefficients

Limitations

• Kw = 1e-14 at 25 °C (not temperature-dependent)
• Not Henderson–Hasselbalch buffer pH
• Not ICE, activity coefficients, or polyprotic