Redox Half-Reaction Balancer 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

t8-005

Effect

Computation or source lookup only

Input and validation requirements

The identical-species input Fe2+ -> Fe2+ forces an electron coefficient of exactly zero. Any implementation that normalizes by electrons transferred can divide by zero or produce an undefined result instead of rejecting the non-redox input. The slash-form convention probe also exposes a direction ambiguity that can reverse the reported half-reaction.

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": {
    "equation": "MnO4^- + Fe^2+ -> Mn^2+ + Fe^3+",
    "medium": "acidic",
    "input_type": "full_redox"
  },
  "expected_outputs": {
    "balanced_half_reactions": [
      "MnO4^- + 8H^+ + 5e^- -> Mn^2+ + 4H2O",
      "Fe^2+ -> Fe^3+ + e^-"
    ],
    "balanced_overall_equation": "MnO4^- + 8H^+ + 5Fe^2+ -> Mn^2+ + 4H2O + 5Fe^3+",
    "electrons_transferred": 5,
    "residual": {
      "Mn": 0,
      "Fe": 0,
      "O": 0,
      "H": 0,
      "charge": 0
    }
  },
  "reference_data": {
    "standard_method": "acidic half-reaction method",
    "oxidation_half": "Fe^2+ -> Fe^3+ + e^-",
    "reduction_half": "MnO4^- + 8H^+ + 5e^- -> Mn^2+ + 4H2O"
  },
  "working": "Reduction half: Mn is already balanced. Put 4H2O on the product side to balance 4 O. Put 8H+ on the reactant side to balance 8 H. Charges are reactants -1 + 8 = +7 and products +2, so add 5e^- to the reactant side: +7 - 5 = +2. Oxidation half: Fe is balanced; charge changes from +2 to +3, so add 1e^- to products. Multiply the iron half by 5. Add: MnO4^- + 8H^+ + 5e^- + 5Fe^2+ -> Mn^2+ + 4H2O + 5Fe^3+ + 5e^-. Cancel 5e^- from both sides. Element arithmetic: Mn 1=1, Fe 5=5, O 4=4, H 8=8. Charge: left -1 + 8 + 10 = +17; right +2 + 15 = +17; residuals are all zero."
}

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-tranche8/tranche8-results.json