Buffer pH (Henderson) API

Computes buffer pH via Henderson-Hasselbalch pH = pKa + log10([A-]/[HA]) from pKa (or Ka) and conjugate-base/weak-acid amounts. Answers 'What is the pH of an acetate buffer with equal A- and HA?', 'buffer pH from a base/acid ratio'.

Price$0.04per request

MethodPOST

Route/v1/chemistry/henderson-hasselbalch

StatusLive

MIME typeapplication/json

Rate limit120/minute

Cache0s public

chemistrybufferhenderson-hasselbalchpkaphacid-baseconjugateequilibrium

API URLhttps://x402.hexl.dev/v1/chemistry/henderson-hasselbalch

Integration docs

Example request

{
  "pKa": 4.75,
  "base": 1,
  "acid": 1
}

Example response

{
  "pKa": 4.75,
  "ratio": 1,
  "pH": 4.75,
  "pOH": 9.25,
  "classification": "acidic",
  "formula": "pH = pKa + log10([A-]/[HA])"
}

Input schema

{
  "type": "object",
  "required": [
    "base",
    "acid"
  ],
  "properties": {
    "pKa": {
      "type": "number",
      "examples": [
        4.75
      ]
    },
    "ka": {
      "type": "number"
    },
    "base": {
      "type": "number",
      "examples": [
        1
      ]
    },
    "acid": {
      "type": "number",
      "examples": [
        1
      ]
    }
  }
}

Output schema

{
  "type": "object",
  "additionalProperties": true
}