pH / Henderson-Hasselbalch Calculator 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

t4-158

Effect

Computation or source lookup only

Input and validation requirements

A zero conjugate-acid concentration causes division by zero, making the pH undefined; the instrument must reject the input rather than force a numeric result. There is also a convention hazard if the ratio direction or logarithm base is not made explicit.

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": {
    "pKa": 4.76,
    "conjugate_base": "0.100 mol/L acetate",
    "conjugate_acid": "0.100 mol/L acetic acid"
  },
  "expected_outputs": {
    "pH": 4.76
  },
  "working": "A-/HA = 0.100 mol/L ÷ 0.100 mol/L = 1. pH = 4.76 + log10(1) = 4.76 + 0 = 4.76."
}

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-tranche4/tranche4-results.json