Henderson-Hasselbalch Equation

[Raymond_Guan_1H]

When is it a allowed to use henderson-hasselbalch equation? Is it when the molarity is fairly low or high? I'm stilled just confused a bit about it.

[Minu Reddy]

The HH equation is used when considering the idea for a buffer that a weak acid and its conjugate base or a weak base and a conjugate acid must be in equal concentrations for optimum buffering capacity. Therefore when you solve the equation considering their equal concentrations, you will get that PH=PKA as demonstrated on pg 170 in the course reader.

Sometimes you will be given the concentrations of the components as well as the PH and you have to solve for the PKa value to pick the best acid.

[derek1d]

Along with this, is there any difference between Ka and pKa? Does the HH equation mean that we will be using pKa?

[Amy Wu 1D]

Along with this, is there any difference between Ka and pKa? Does the HH equation mean that we will be using pKa?

Ka and pKa are different in that pKa is equal to -log(Ka) and yeah, the HH equation uses pKa. The full equation is on pg. 167 of the course reader if you need it.