Which one of the following tests used for the identification of functional groups in organic compounds does not use copper reagent?

Acidic ferric chloride solution on treatment with excess of potassium ferrocyanide gives a Prussian blue coloured colloidal species. It is :

Which one of the following complexes is violet in colour?

To an aqueous solution containing ions such as Al³⁺, Zn²⁺, Ca²⁺, Fe³⁺, Ni²⁺, Ba²⁺ and Cu²⁺ was added conc. HCl, followed by H₂S.

The total number of cations precipitated during this reaction is/are :