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

Coordination compounds have great importance in biological systems. In this context,which of the following statements is incorrect?

Identify the complexes formed in the following processes:
$I$. Mond's process for purification of nickel
$II$. Removal of unreacted $AgBr$ from photographic plates
$III$. Removal of lead poisoning from the body

$A$ metal complex absorbed orange light. The colour in which it appears is

Prussian blue is due to the formation of

$PCl_5$ reacts with finely divided silver on heating and a white silver salt is obtained,which dissolves on adding excess aqueous $NH_3$ solution. Write the reactions involved to explain what happens.