Solution Mixing / Neutralization 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

t4-027

Effect

Computation or source lookup only

Input and validation requirements

• Division by zero occurs if V1+V2=0; reject zero or negative total volume.
• Unit mismatch, such as multiplying molarity by milliliters without converting to liters, creates a factor-of-1000 error.
• The neutralization calculation must reject or explicitly handle negative concentrations and negative volumes.
• pH calculation is undefined if an excess-reagent concentration is zero unless water autoionization or an appropriate equilibrium model is used.
• Using pH=-log10(excess concentration) for a weak acid/base, polyprotic species, buffer, or equivalence point can be materially wrong.
• Acid/base stoichiometric coefficients must be included; a generic H+ versus OH- comparison is not sufficient for species such as H2SO4, H3PO4, Ca(OH)2, or weak electrolytes.
• The implementation needs an explicit policy for non-additive volumes, activity corrections, temperature dependence of Kw, precipitation, gas evolution, and reactions other than neutralization.

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": {
    "operation": "same-solute_mixing",
    "solute": "NaCl",
    "C1_M": 0.2,
    "V1_L": 0.15,
    "C2_M": 0.05,
    "V2_L": 0.35
  },
  "expected_outputs": {
    "total_moles_mol": 0.0475,
    "total_volume_L": 0.5,
    "C_final_M": 0.095
  },
  "working": "n1=C1V1=0.200×0.150=0.0300 mol. n2=C2V2=0.050×0.350=0.0175 mol. n_total=0.0300+0.0175=0.0475 mol. V_total=0.150+0.350=0.500 L. C_final=n_total/V_total=0.0475/0.500=0.0950 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-tranche4/tranche4-results.json