1. What is pKa?

pKa is the negative base-10 logarithm of the acid dissociation constant (Ka) of a solution. It indicates the strength of an acid in solution, with lower values corresponding to stronger acids.

2. How Does the Calculator Work?

The calculator predicts pKa values based on:

Where:

• Structure — Molecular structure features that influence acidity
• Composition — Chemical composition and functional groups
• Method — Prediction algorithm used (empirical, quantum, or ML)

Explanation: The calculator uses structural and compositional features to estimate the acid dissociation constant.

3. Importance of pKa Prediction

Details: Accurate pKa prediction is crucial for drug design, chemical synthesis, and understanding biochemical processes.

4. Using the Calculator

Tips: Enter molecular structure (SMILES notation recommended), chemical composition, and select prediction method.

5. Frequently Asked Questions (FAQ)

Q1: What's the accuracy of pKa prediction?
A: Accuracy varies by method, typically ±0.5-1.0 pKa units for good quality predictions.

Q2: What are typical pKa values?
A: Most organic acids have pKa between 0-20, with common values 3-5 for carboxylic acids, 9-10 for phenols.

Q3: Why predict pKa from structure?
A: Experimental determination can be time-consuming; prediction allows rapid screening of compounds.

Q4: What structures are hard to predict?
A: Complex polyprotic systems, molecules with strong intramolecular interactions, and certain heterocycles.

Q5: Can I predict pKa for bases?
A: Yes, the calculator can also predict pKa for basic groups (equivalent to pKb conversion).