# plz tell me some short tricky formulae to solve numerical prob. on this topic .. what is the formulae for finding the pH.......?

Aman Bansal
592 Points
11 years ago

Dear Nivi,

pH is defined as the negative logarithm of the H+ concentration.
pH = - log [H+]

A logarithm is an exponent. It is the exponent you have to put on the base number (which is 10 for common logs) to get the original quantity.

pH = - log [H+], so
-pH = log [H+]
-pH is the exponent you have to put on the base 10 to get the [H+]
10^-pH = [H+]

The equation in your question is called the Henderson-Hasselbalch equation. It is used for finding the pH of a buffer solution. In this equation:
Ka = acid dissociation (ionization) constant of the weak acid.
pKa = - log Ka
A- is the anion base of the conjugate acid HA.

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Aman Bansal