Source: https://guthlabs.ai/docs/instruments/titration-equivalence-point-calculator/mechanism/

instrument mechanism / verified-clean

# Titration Equivalence-Point Calculator mechanism

The inspectable method record for Titration Equivalence-Point Calculator, kept separate from implementation and qualification.

Status: **VERIFIED_CLEAN**Lifecycle: **verified-clean**

## Model scope

The formula itself is standard and correct under the stated unit and stoichiometry assumptions. The specification needs an explicit operating mode and unambiguous parameter roles before it can pass: either calculate an unknown concentration from a measured equivalence volume, or calculate equivalence volume from known concentrations and analyte amount. It cannot infer both independently from the currently listed inputs.

- The equation C_a·V_a·n_a=C_b·V_b·n_b is the standard stoichiometric equivalence relation, provided n_a and n_b are defined as the reacting stoichiometric coefficients or equivalents per mole.

- The declared inputs do not specify which solution has known concentration, which concentration is unknown, or whether the unknown concentration is that of the analyte or titrant.

- The stated inputs are insufficient to compute both unknown concentration and equivalence volume independently: concentration determination requires a measured equivalence volume, while equivalence-volume prediction requires both solution concentrations and the analyte amount.

- The formula is valid at a stoichiometric equivalence point, but the specification does not state how polyprotic acids, polybasic bases, or reaction-specific stoichiometric coefficients are selected.

## Units and conventions

- C_a and C_b must use the same concentration units, such as mol/L.

- V_a and V_b must use the same volume units; the test calculations use liters internally and report milliliters where noted.

- n_a and n_b are dimensionless stoichiometric coefficients. They must not be silently confused with acidity or basicity labels unless the reaction stoichiometry supports that interpretation.

- The reaction must be specified so that the appropriate balanced-equation coefficients are known.

## Inspectable vector

One of 4 source-bound review vectors:

````
{
  "inputs": {
    "mode": "standardize_unknown_titrant",
    "known_solution": "acid",
    "C_a_M": 0.1,
    "V_a_L": 0.025,
    "n_a": 1,
    "V_b_L": 0.0246,
    "n_b": 1
  },
  "expected_outputs": {
    "unknown_titrant_concentration_C_b_M": 0.1016260163
  },
  "working": "C_a·V_a·n_a=C_b·V_b·n_b\nC_b=(C_a·V_a·n_a)/(V_b·n_b)\nC_b=(0.1000 mol/L × 0.02500 L × 1)/(0.02460 L × 1)\nC_b=0.002500 mol ÷ 0.02460 L\nC_b=0.1016260163 mol/L ≈ 0.1016 M"
}
````

## Failure boundary

**BREAK_CLAIMED** · SELF_FLAGGED

The zero measured-titrant-volume input produces a division by zero in the standardized concentration calculation. The specification also does not define stoichiometric branch selection, so assuming the wrong n_a:n_b ratio can produce a factor-of-two error.

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/titration-equivalence-point-calculator/>)[03**Implementation**](<https://guthlabs.ai/docs/instruments/titration-equivalence-point-calculator/implementation/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/titration-equivalence-point-calculator/qualification/>)

## 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`

- `BOUNDARY_HAZARD_CATALOG.json`