pKa
Science & Engineering abbreviation · Chemistry
| Stands for | Acid dissociation constant (negative logarithm) |
|---|---|
| Categories | Science & Engineering |
pKa stands for Acid dissociation constant (negative logarithm), a chemistry abbreviation.
Measure of acid strength: the negative base-10 logarithm of the acid dissociation constant, Ka. Lower pKa means a stronger acid; acetic acid has a pKa of about 4.76, and a solution's pH equals the pKa when the acid is half dissociated, the basis of buffer design.
Example: With a pKa of 7.2, phosphate is a good buffer for experiments near neutral pH.
Usage notes
The "p" follows the same convention as pH. Medicinal chemists track pKa because it determines whether a drug is charged at the body's pH of about 7.4, which affects absorption. For a conjugate acid-base pair in water at 25 °C, pKa + pKb = 14. Values measured in solvents such as DMSO can differ greatly from those in water.
Related abbreviations
More chemistry abbreviations
- PEG – Polyethylene glycol (laxative and bowel preparation)
- PET – Polyethylene terephthalate
- PFAS – Per- and polyfluoroalkyl substances
- PFOA – Perfluorooctanoic acid
- PFOS – Perfluorooctanesulfonic acid
- pH – Potential of hydrogen
- PLA – Polylactic acid
- PMMA – Poly(methyl methacrylate)
- PP – Polypropylene
- ppt – Precipitate
- PS – Polystyrene
- PTFE – Polytetrafluoroethylene