What is the pH range of Oxalic acid?

2 Answers

justaguide's profile pic

justaguide | College Teacher | (Level 2) Distinguished Educator

Posted on

The acid dissociation constant is a value defined for every acid HA and denoted by Ka = [H+][A-]/[HA]

The acid dissociation constant of oxalic acid is 5.60×10^-2 and 5.42×10^-5. There are two values as oxalic acid is a poly protic acid and has a chemical formula HOOCCOOH.

5.60×10^-2 = [H+][HC2O4-]/[HOOCCOOH]

5.42×10^-5 = [H+][C2O4 2-]/[C2O4H-]

From the Ka value the value of pH can be derived as :

pH = pKa + log[A-]/[HA]

pKa is defined as the negative of the log to the base 10 of Ka, or pKa = -log Ka

At half neutralization the pH of an acid is given by pH = pKa + 0 as log ([A-]/[HA]) = log 1 = 0. For oxalic acid this ranges between –log(5.60×10^-2 ) = 1.25 and –log(5.42×10^-5 ) = 4.267.

iwalkalone's profile pic

iwalkalone | Student, Grade 10 | eNotes Newbie

Posted on


frst of all pka is The negative logarithm of the acid dissociation constant, Ka.

Just like the pH, the pKa tells you of the acid or basic properties of a substance.

Oxalic acid has pKa values of 1.27 and 4.27

hope it hepled.....!! :)