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pKb given Dissociation constant of Weak Base Calculator

Formula Used:

\[ pK_b = -\log_{10}(K_b) \]

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1. What is pKb?

Definition: pKb is the negative base-10 logarithm of the base dissociation constant (Kb) of a weak base.

Purpose: It provides a convenient way to express the strength of weak bases on a logarithmic scale, similar to how pH works for acidity.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ pK_b = -\log_{10}(K_b) \]

Where:

Explanation: The smaller the pKb value, the stronger the base. A change of 1 in pKb represents a 10-fold difference in base strength.

3. Importance of pKb Calculation

Details: pKb values are crucial in chemistry for predicting base strength, buffer solutions, and reaction equilibria involving weak bases.

4. Using the Calculator

Tips: Enter the dissociation constant (Kb) of the weak base. The value must be between 0 and 1 (typically very small numbers like 1×10-5).

5. Frequently Asked Questions (FAQ)

Q1: What does a high pKb value indicate?
A: A high pKb indicates a weaker base, as it corresponds to a smaller Kb value.

Q2: How is pKb related to pKa?
A: For any conjugate acid-base pair: pKa + pKb = 14 (at 25°C in water).

Q3: What's a typical pKb range for weak bases?
A: Most weak bases have pKb values between 2 and 12 in aqueous solutions.

Q4: Why use logarithmic scale for Kb?
A: The logarithmic scale compresses the wide range of Kb values (often spanning 10 orders of magnitude) into more manageable numbers.

Q5: Can pKb be negative?
A: Yes, if Kb > 1, which would indicate a very strong base (though such bases are rare in aqueous solutions).

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