Answer :

Sure, let's discuss the colors of the given salts in detail:

a. [tex]\(Fe_2(SO_4)_4\)[/tex]
- This compound is Iron(III) Sulfate. Iron(III) sulfate typically appears in yellow or brownish-yellow color. This color results from the oxidation state of iron in the compound.

b. [tex]\(C_4SO_4\)[/tex]
- This formula does not correspond to any known common compound. It is important to recognize that some chemical formulas might not represent any known existing salts. Since there is no known common compound with the formula [tex]\(C_4SO_4\)[/tex], the color of this salt is unknown.

c. [tex]\(FeCl_2\)[/tex]
- This compound is Iron(II) Chloride. Iron(II) chloride typically has a green color. This color is characteristic of the +2 oxidation state of iron in combination with chloride ions.

d. [tex]\(Na_2CO_3\)[/tex]
- This compound is Sodium Carbonate. Sodium carbonate typically appears white. It is a common white crystalline solid.

To summarize:
- [tex]\(Fe_2(SO_4)_4\)[/tex] is yellow or brownish-yellow.
- [tex]\(C_4SO_4\)[/tex] is an unknown compound and its color is not known.
- [tex]\(FeCl_2\)[/tex] is green.
- [tex]\(Na_2CO_3\)[/tex] is white.