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Ka = 10^(-pKa):
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Ka (acid dissociation constant) is a quantitative measure of the strength of an acid in solution. pKa is the negative logarithm of Ka, making it easier to work with very small numbers. The relationship between them is fundamental in acid-base chemistry.
The calculator uses the mathematical relationship:
Where:
Explanation: This conversion allows chemists to easily switch between the logarithmic pKa scale and the linear Ka scale, which is particularly useful for calculations involving acid strength and equilibrium constants.
Details: Knowing Ka values is essential for predicting the extent of acid dissociation, calculating pH of solutions, understanding buffer systems, and designing chemical processes in pharmaceuticals, biochemistry, and industrial chemistry.
Tips: Enter the pKa value as a positive number. The calculator will compute the corresponding Ka value. pKa values typically range from -10 (strong acids) to 50 (very weak acids).
Q1: What does a lower pKa value indicate?
A: A lower pKa value indicates a stronger acid, as it corresponds to a larger Ka value and greater dissociation in water.
Q2: Can pKa be negative?
A: Yes, pKa can be negative for very strong acids like hydrochloric acid (HCl, pKa ≈ -7), indicating extremely large Ka values.
Q3: How is Ka related to acid strength?
A: The larger the Ka value, the stronger the acid. Strong acids have Ka > 1, while weak acids have Ka < 1.
Q4: What's the difference between Ka and pKa?
A: Ka is the actual equilibrium constant, while pKa is its negative logarithm. pKa provides a more convenient scale for comparing acid strengths.
Q5: Why use logarithmic scale for pKa?
A: The logarithmic scale compresses the wide range of Ka values (from 10^10 to 10^-50) into a more manageable range of pKa values (-10 to 50).