Thickness of reaction layer

{
  "id": "MLC-T-CHM-011997",
  "term": "Thickness of reaction layer",
  "field": "Chemistry",
  "definition": "The distance from an electrode surface beyond which the deviation from chemical equilibrium between an electroactive substance and its precursor is negligible, when that equilibrium is re-established at a finite rate while a kinetic current flows. Within this layer mass transfer and the chemical reaction both affect the concentrations. For a first-order reaction its thickness is approximately the square root of D/k, where D is the diffusion coefficient and k the rate constant.",
  "subject": "Analytical Chemistry",
  "see_also": [
    "chemical equilibrium",
    "electroactive substance",
    "kinetic current"
  ],
  "references": [
    "PAC, 1985, 57, 1491. 'Recommended terms, symbols, and definitions for electroanalytical chemistry (Recommendations 1985)' on page 1504 (https://doi.org/10.1351/pac198557101491)"
  ],
  "url": "https://mlchart.com/terminology/chemistry/thickness-of-reaction-layer/"
}