What is the difference between pka and ph

Reeshabh Ranjan Reeshabh Ranjan 1, 3 3 gold badges 20 20 silver badges 37 37 bronze badges. Add a comment. Active Oldest Votes. Improve this answer. Yunfei Ma Yunfei Ma 1, 2 2 gold badges 16 16 silver badges 28 28 bronze badges. MaxW MaxW ChemPebble ChemPebble 26 4 4 bronze badges. Sign up or log in Sign up using Google. Sign up using Facebook. Sign up using Email and Password. Post as a guest Name.

Email Required, but never shown. Featured on Meta. From these numbers, you know that ethoxide is the stronger base. Do not make the mistake of using the pK a value of this is the pK a of ammonia acting as an acid , and tells you how basic the NH 2 - ion is very basic! Biochemistry and organic chemistry texts often list the value as These texts have incorrectly factored the molar value for the concentration of water into the equilibrium constant.

The correct derivation of the equilibrium constant involves the activity of water, which has a value of 1. While this course begins with single functional groups, we will eventually work with interesting compounds containing multiple functional groups. Recognizing which hydrogens can be ionized as acidic protons and which hydrogens can NOT, is a useful skill.

Notice in this example that we need to evaluate the potential acidity at four different locations on the molecule. Aldehyde and aromatic protons are not at all acidic pK a values are above 40 — not on our table. The two protons on the carbon next to the carbonyl are slightly acidic, with pK a values around according to the table. The most acidic proton is on the phenol group, so if the compound were to be subjected to a single molar equivalent of strong base, this is the proton that would be donated.

Therefore, the pH values more than 7 indicate basicity. As the basicity increases, pH value will also increase and strong bases will have pH value Therefore, in a situation like that, pOH can be determined from —log [OH — ] value. There are pH meters and pH papers in laboratories, which can be used to measure pH values directly.

Acidity is the state of being an acid. This is related to the degree of being an acid. K a is the acid dissociation constant. It gives an indication of the ability of a weak acid, to lose a proton. In an aqueous medium, a weak acid is in equilibrium with its conjugate base as shown in the example below.