Question

Classify $Na{{H}_{2}}P{{O}_{2}}$ and $NaHS{{O}_{4}}$ salts as acid salt or normal salt.

Answer 1

Hint: In oxoacids, the hydrogen atom that is attached to the oxygen atom causes the acidic nature of the oxoacids. So if the compound has more than one acidic hydrogen atom then the resulting salt will be acidic, and if the compound has only one acidic hydrogen atom then the resulting salt is normal or neutral.

Complete step by step answer:
-Both compounds given in the question are salts of oxoacids of respective elements. In $Na{{H}_{2}}P{{O}_{2}}$, phosphorus is the central atom, so it must be salt of oxoacids of phosphorus. In $NaHS{{O}_{4}}$, sulfur is the central atom, so it must be salt of oxoacids of sulfur.
-In oxoacids, the hydrogen atom that is attached to the oxygen atom causes the acidic nature of the oxoacids. So if the compound has more than one acidic hydrogen atom then the resulting salt will be acidic, and if the compound has only one acidic hydrogen atom then the resulting salt is normal or neutral.
-So the $Na{{H}_{2}}P{{O}_{2}}$, is the salt of ${{H}_{3}}P{{O}_{2}}$, there is only one acidic hydrogen atom is present as you can see in the diagram:

-So this hydrogen is substituted with sodium metal, so it is a normal or neutral salt.
-The $NaHS{{O}_{4}}$, is the salt of ${{H}_{2}}S{{O}_{4}}$, in ${{H}_{2}}S{{O}_{4}}$ there are two acidic hydrogen atoms are present as you can see in the diagram:

-So one hydrogen atom is substituted with sodium metal or partial substitution takes place, so it is an acid salt.

Note: The pH of the neutral salt or normal salt ranges from 5-7 and does not show any acidic or basic nature. Acid salt is always formed by incomplete replacement of hydrogen atoms.