transition metal reactions

Question 1

how do you produce Cr2O7 2- from Cr 3+?

Answer 1

react Cr 3+ with H2O2 which produced CrO4 2-

then acidify CrO4 2- to produce Cr2O7 2- (this is an equillibrium)

Question 2

why is H2O only a monodentate ligand?

Answer 2

to be bidentate a molecule must have 2 different atoms with lone pairs

Question 3

how many daitive covalent bonds can EDTA- form?

Answer 3

6