Pka vs pH

[505968276]

Hi, I was wondering what the relationship between pH and Pka is and how you can use those values to know whether the predominant species is charged or neutral?

[106033555]

all i know is that pka tells you the strenght of the acid, so the higher the pka, the weaker the acid. but i dont know how to check if these are either charged or neutral.

[306278293]

We can use pH values to determine whether or not the solution is acidic or basic (low pH = acidic, high pH = basic) and can be found using -log[H^+]. Similarly, pKa is the -log(Ka), with Ka being the equilibrium constant, or more specifically the "acid dissociation constant" and we are able to distinguish is a solution is acidic if it has a high Ka and low pKa and if it is basic with a low Ka and high pKa.

In this sense, pH and pKa have similar techniques to determining whether or not a solution is acidic or not; a low pH and low pKa means it is acidic and a high pH and high pKa means it is basic.

Hope this helped a little!

[906112539]

Hi, I was wondering what the relationship between pH and Pka is and how you can use those values to know whether the predominant species is charged or neutral?

pH measures the acidity based on the concentration of H ions, whereas pKa measures the strength of acidity using the Ka value. If pH is less than When the pH of a solution is less than the pKa of the acid, then the predominant species is (HA). But if pKa is less than pH, the conjugate base dominates, (A-).

[RandyRich]

pH measures the hydrogen ions in solution, and a low pH means high acidity. pKa acts similarly/proportionally to pH, in that lower values of pKa are more acidic as well. When pH and pKa are equal then the solution has equal quantities of conjugate acid and base. If pKa is larger(ie less acidic) than pH then there is a greater proportion of H+ and the solution is positively charged. If pKa is smaller than pH, then there is less H+ the environment is more negatively charged and more basic.

[Averie Moore 2F]

pKa and pH are related through the concentrations of the acid and its conjugate base or base and its conjugate acid. You can use it to determine the ionization state because if the pH of a solution is lower than the pKa of an acid, the acid will be in its charged form and if the pH of a solution is higher than the pKa of an acid, the acid will be in its neutral form.