Why do some acids have multiple pKa values?

A molecule with two pKa values indicates the presence of two different inonizable functional groups. for example salicylic acid has two pKa values one is 4 which is for carboxylic acid group and the other is 14 which is for hydroxyl group of salicylic acid molecule.

Why oxalic acid is stronger than malonic acid?

In oxalic acid, there is no electron releasing group so it is more acidic in comparison of malonic as well as pimelic acid contains an electron releasing group which makes the malonic and pimelic acid less acidic.

Why malonic acid is weaker than oxalic acid?

So, Oxalic acid (COOH-COOH) is more acidic than formic acid (HCOOH). Malonic acid, (COOH−CH2−COOH) is less acidic than oxalic acid because of the intervening presence of −CH2 group and succinic acid (COOH−CH2−CH2−COOH) which is much weaker than (COOH−CH2−COOH).

Why are pKa values different?

A pKa may be a small, negative number, such as -3 or -5. It may be a larger, positive number, such as 30 or 50. The lower the pKa of a Bronsted acid, the more easily it gives up its proton. The higher the pKa of a Bronsted acid, the more tightly the proton is held, and the less easily the proton is given up.

Why does oxalic acid have two PKAS?

The reason is that as soon as the first acidic proton comes off, we have formed an anion. And it’s harder to remove a H from an anion than from a neutral molecule. The second ionization will be weaker (higher pKa value) than the first. And the third weaker than the second, as in citric acid, for example.

Why does malic acid have 2 pKa values?

Since malic and tartaric acid both have two protons which may be lost to the solution, there are two pKa values for each acid.

Why is oxalic acid a strong acid?

Oxalic acid is a weak acid and will only partially ionize in an aqueous solution. There are two acidic protons in oxalic acid. The first ionization produces HC2O4-, which is also a weak acid and will also ionize.

Why oxalic acid is an acid?

Oxalic acid is an organic acid with the IUPAC name ethanedioic acid and formula HO2C−CO2H. It is the simplest dicarboxylic acid. Oxalic acid has much greater acid strength than acetic acid. It is a reducing agent and its conjugate base, known as oxalate (C2O2−4), is a chelating agent for metal cations.

Why is the second carboxylic acid in oxalic acid so much less acidic than the first?

double bond in the carboxylate ion stabilizes the negative charge that is produced by ionization of the carboxyl group; however, Ka2 is lower than K1 because the presence of a carboxylate ion reduces the acidity of the second carboxyl group due to the electrostatic repulsion between the two negative charges on the …

What is the relationship between the pKa of an acid and the pH of its surrounding environment?

The lower the pH, the higher the concentration of hydrogen ions [H+]. The lower the pKa, the stronger the acid and the greater its ability to donate protons. pH depends on the concentration of the solution. This is important because it means a weak acid could actually have a lower pH than a diluted strong acid.

What is the pKa of malonic acid?

2.43
3D Structure for HMDB0000691 (Malonic acid)