Identify the number of donor groups present in $EDTA$.

Which of the following ligands are ambidentate?
$P: NO_3^-$,$Q: NO_2^-$,$R: CN^-$,$S: SCN^-$

Generally,a group of atoms can function as a ligand if:

Turnbull's blue is

Sodium thiosulphate is used to remove the unexposed $AgBr$ from photographic films by forming a complex. In this complex of silver,the coordination number of silver is

Identify the cationic complex from the following.