Question

Rank each of the following ions from most acidic (1) to least acidic (4).

a) H₃PO₄

b) H₂PO₄⁻

c) HPO₄²⁻

d) PO₄³⁻

Answer 1

The ions can be ranked from most acidic to least acidic as follows: H₃PO₄, H₂PO₄⁻, HPO₄²⁻, PO₄³⁻

Step-by-step explanation:

The acidity of an ion is determined by its ability to donate a proton (H+ ion) in a solution. The higher the concentration of H+ ions, the more acidic the solution. In this case, we can rank the ions from most acidic to least acidic as follows:

1. H₃PO₄: This is a triprotic acid, meaning it can donate three protons. It is the most acidic among the given ions.
2. H₂PO₄⁻: This is the conjugate base of H₃PO₄. It can donate two protons and is less acidic than H₃PO₄.
3. HPO₄²⁻: This is the conjugate base of H₂PO₄⁻. It can donate one proton and is less acidic than H₂PO₄⁻.
4. PO₄³⁻: This is the conjugate base of HPO₄²⁻. It cannot donate any protons and is the least acidic among the given ions.