Weak Acid/Base Ionization Solver (ICE table) implementation

Binding contract

This record describes what an executable surface must bind and validate. It does not claim that a public calculator, package, or production route is deployed.

Record owner

Guth Instruments

Lifecycle

verified-clean

Evidence ID

t6-048

Effect

Computation or source lookup only

Input and validation requirements

The specification has several hazardous edge conditions: C0=0 produces undefined percent ionization and pH, Ka=0 produces [H+]=0 and therefore undefined pH, and a 5% approximation branch changes behavior near the validity boundary. Base calculations also require an explicit OH−/H+ and temperature convention.

Required corrections

No binding erratum is attached to this unique-name record. Implementers must still preserve the declared units, domain, and failure behavior.

Inspectable interface fixture

The sample below is evidence for interface and validation tests, not a production implementation.

{
  "inputs": {
    "species": "weak acid",
    "Ka": 0.000018,
    "C0_M": 0.1,
    "method": "quadratic"
  },
  "expected_outputs": {
    "equilibrium_H_plus_M": 0.001332671,
    "pH": 2.87528,
    "percent_ionization": 1.332671,
    "ICE_table": {
      "HA_M": [
        "0.100000",
        "-0.001332671",
        "0.098667329"
      ],
      "H3O_plus_M": [
        "0",
        "+0.001332671",
        "0.001332671"
      ],
      "A_minus_M": [
        "0",
        "+0.001332671",
        "0.001332671"
      ]
    }
  },
  "working": "Let x=[H3O+]. Ka=x²/(C0−x), so x²+Ka·x−Ka·C0=0. Discriminant D=Ka²+4KaC0=(0.000018)²+4(0.000018)(0.100000)=0.000000000324+0.000007200000=0.000007200324. sqrt(D)=0.002683342. Positive root x=(−0.000018+0.002683342)/2=0.001332671 M. Percent ionization=(0.001332671/0.100000)×100=1.332671%. pH=−log10(0.001332671)=2.87528. ICE final values: HA=0.100000−x=0.098667329 M; H3O+=x=0.001332671 M; A−=x=0.001332671 M."
}

Other records

Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

• VERIFIED_LEDGER.json
• evidence-tranche6/tranche6-results.json