What ion is inferred when a violet sublimate forms along the test tube's interior after adding 1 mL of a salt solution neutralized with HCl, followed by 1 mL of carbon disulfide, and subsequently adding an excess of chlorine water drop by drop and shaking the test tube?
1. \(Cl^-\)
2. \(I^-\)
3. \(SO_4^{2-}\)
4. \(CO_3^{2-}\)