$Fe^{3+}$ cation gives a Prussian blue precipitate on addition of potassium ferrocyanide solution due to the formation of:

Assign $A, B, C, D$ from the given type of reaction.
$K_4[Fe(CN)_6] + 2CuSO_4 \longrightarrow Cu_2[Fe(CN)_6] \downarrow + 2K_2SO_4$

Prussian blue is due to the formation of

The mismatched combinations are
$A.$ Chlorophyll $- Co$
$B.$ Water hardness $- EDTA$
$C.$ Photography $- [Ag(CN)_2]^-$
$D.$ Wilkinson catalyst $- [(Ph_3P)_3RhCl]$
$E.$ Chelating ligand $- D^{-}$\text{Penicillamine}
Choose the correct answer from the options given below:

Hypo is used in photography because of its:

Identify $(A)$ to $(E)$ and also explain the reactions involved.
$CuCO_3 \to CuO$ $\xrightarrow{\text{Heat with } CuS} (A)$ $\xrightarrow{\text{conc. } HNO_3} (B)$ $\xrightarrow{NH_{3(aq)}} (C) \text{ (Blue solution)}$
$CuCO_3 \to (D)$ $\xrightarrow{Ca(OH)_2} (E) \text{ (Milky)}$ $\xrightarrow{CO_2} Ca(HCO_3)_2 \text{ (Clear solution)}$