What is the standard definition of pKa in terms of Ka?

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Multiple Choice

What is the standard definition of pKa in terms of Ka?

Explanation:
pKa is defined as the negative base-10 logarithm of Ka: pKa = -log10 Ka. This means that as Ka (the acid dissociation constant) grows, the pKa falls, so stronger acids have smaller pKa values and weaker acids have larger pKa values. The use of the negative common logarithm converts the often tiny Ka values into a more convenient, positive scale. For example, acetic acid has Ka about 1.8×10^-5, giving pKa around 4.74. Using a natural log would give different numbers, which is why the standard definition uses the base-10 logarithm.

pKa is defined as the negative base-10 logarithm of Ka: pKa = -log10 Ka. This means that as Ka (the acid dissociation constant) grows, the pKa falls, so stronger acids have smaller pKa values and weaker acids have larger pKa values. The use of the negative common logarithm converts the often tiny Ka values into a more convenient, positive scale. For example, acetic acid has Ka about 1.8×10^-5, giving pKa around 4.74. Using a natural log would give different numbers, which is why the standard definition uses the base-10 logarithm.

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