An equation showing the relationship between a buffer’s pH and the relative amounts of the buffer’s weak acid and its conjugate base is called as Henderson-Hasselbalch equation.

**Henderson–Hasselbalch equation**

An
equation showing the relationship between a buffer’s pH and the relative
amounts of the buffer’s weak acid and its conjugate base is called as
Henderson-Hasselbalch equation. Consider the dissociation of a weak acid (HA).
At equilibrium,

HA ↔H^{+} + A^{–}

^{ }

The
dissociation constant (K_{a}) is,

Reciprocating the log term of
equation 1.5

This form of the ionization constant
equation is called the Henderson-Hasselbalch equation (equation 1.6). It is
useful for calculating the pH of a weak acid solution containing its conjugate
base (salt). The other forms of the Henderson-Hasselbalch equation of weak acid
with its conjugate base are as follows:

When the concentrations of weak acid
and its conjugate base or weak base and its conjugate acid are equal, the pH of
the solution equals the pK_{a} of the buffer. This is evident from the
Henderson-Hasselbalch equation.

If the pK_{a} of bicarbonate
buffer is 6.1 and the pH of blood is 7.4, then the ratio of bicarbonate to
carbonic acid ([HCO_{3}^{–}] / [H_{2}CO_{3}])
in blood is calculated by applying the Henderson-Hasselbalch equation.

Study Material, Lecturing Notes, Assignment, Reference, Wiki description explanation, brief detail

**Related Topics **

Copyright © 2018-2021 BrainKart.com; All Rights Reserved. (BS) Developed by Therithal info, Chennai.