$A$ solution when treated with dimethyl glyoxime gives a rose red complex. The metal present is

Write the application of coordination compounds in black and white photography.

$A$ blood-red colour is obtained when $Ferric$ $Chloride$ solution reacts with

The wrong match is:

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

The iron salt used in blue prints is