Answer:
c. Cr
Explanation:
[tex]Cr^3+(aq) + CO_3^2-(aq) ------------> Cr_2CO_3(s)[/tex]
The compound is containing [tex]CO_3^2-[/tex] ion.
If acid reacts with it, CO_2 evolves.
[tex]H^+ + CO_3^2- ----------> H_2O + CO_2[/tex]
therefore, Cr would form a precipitate when added to an aqueous solution of this compound. Cr2CO3 is the precipitate.