polyproctic acids and slats what do they do?

Answer 1

Maybe a chemical equation will make it easier to understand:

If a proyprotic acid (Species (I) (more one available H) dissociates in water, it will form to an intermediate (Species II) which will also be able to dissociate again (Species (III):

Lets look at carbonic acid H2CO3(Species (I))

H2CO3(aq) --> H+(aq) + HCO3-(aq) (Species(II))

HCO3-(aq) --> H+(aq) + CO3-2(aq) (Species (III))

Answer 2

Polyprotic acids are able to donate more than one proton per acid molecule, in contrast to monoprotic acids that only donate one proton per molecule. Specific types of polyprotic acids have more specific names, such as diprotic acid (two potential protons to donate) and triprotic acid (three potential protons to donate).

A monoprotic acid can undergo one dissociation (sometimes called ionization) as follows and simply has one acid dissociation constant as shown above:

HA(aq) + H2O(l) ⇌ H3O+(aq) + A−(aq) Ka
A diprotic acid (here symbolized by H2A) can undergo one or two dissociations depending on the pH. Each dissociation has its own dissociation constant, Ka1 and Ka2.

H2A(aq) + H2O(l) ⇌ H3O+(aq) + HA−(aq) Ka1
HA−(aq) + H2O(l) ⇌ H3O+(aq) + A2−(aq) Ka2
The first dissociation constant is typically greater than the second; i.e., Ka1 > Ka2 . For example, sulfuric acid (H2SO4) can donate one proton to form the bisulfate anion (HSO4−), for which Ka1 is very large; then it can donate a second proton to form the sulfate anion (SO42−), wherein the Ka2 is intermediate strength. The large Ka1 for the first dissociation makes sulfuric a strong acid. In a similar manner, the weak unstable carbonic acid (H2CO3) can lose one proton to form bicarbonate anion (HCO3−) and lose a second to form carbonate anion (CO32−). Both Ka values are small, but Ka1 > Ka2 .

A triprotic acid (H3A) can undergo one, two, or three dissociations and has three dissociation constants, where Ka1 > Ka2 > Ka3 .

H3A(aq) + H2O(l) ⇌ H3O+(aq) + H2A−(aq) Ka1
H2A−(aq) + H2O(l) ⇌ H3O+(aq) + HA2−(aq) Ka2
HA2−(aq) + H2O(l) ⇌ H3O+(aq) + A3−(aq) Ka3
An inorganic example of a triprotic acid is orthophosphoric acid (H3PO4), usually just called phosphoric acid. All three protons can be successively lost to yield H2PO4−, then HPO42−, and finally PO43− , the orthophosphate ion, usually just called phosphate. An organic example of a triprotic acid is citric acid, which can successively lose three protons to finally form the citrate ion. Even though the positions of the protons on the original molecule may be equivalent, the successive Ka values will differ since it is energetically less favorable to lose a proton if the conjugate base is more negatively charged.

Answer 3

Its Polyprotic acids and salts.

Acids containing more than 2 ionisable Hydrogens are called polyprotic.