Ethylenediaminetetraacetic acid $(EDTA)$ is the antidote for lead poisoning. It is administered in the form of

Match the metal in column $I$ with the coordination compounds/enzymes in column $II$.

Column $I$ (Metals)	Column $II$ (Coordination compounds)
$a. Co$	$i. \text{Wilkinson catalyst}$
$b. Zn$	$ii. \text{Chlorophyll}$
$c. Rh$	$iii. \text{Vitamin } B_{12}$
$d. Mg$	$iv. \text{Carbonic anhydrase}$

When conc. $H_2SO_4$ is treated with $K_4[Fe(CN)_6]$,$CO$ gas is evolved. If dilute $H_2SO_4$ is used instead of conc. $H_2SO_4$,the gas evolved is:

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

Discuss briefly,giving an example in each case,the role of coordination compounds in:
$(i)$ biological systems
$(ii)$ medicinal chemistry
$(iii)$ analytical chemistry
$(iv)$ extraction/metallurgy of metals

The formation of Prussian blue color by ferric ions is due to the formation of which compound?