Transition Metals Flashcards
How to confirtm presence of ammonium ions
Add NaOH and gently warm mixture
OH- + NH4+ -> NH3 + H2O
Moisten piece of red litmus paper and hold over test tube and paper will turn blue if ammonia gas present hence confirming ammonium ions orginially present in sample
What colour does CU 2+ produce with OH- / NH3 AND WHAT WITH EXCESS NH3
Blue but deep blue with excess NH3
What colour does Cr3+ produce with OH- / NH3 adn what with EXCESS NH3 AND NAOH
Dark green solution but purple with excess NH3 AND NAOH
What ion can zinc and scandium only form
Zn2+ / Sc3+
Why are zinc and scandium not transition elemtns
As they do not have incomplete d orbital as zn2+ is 4s0 3d10 and Sc is 4s0 3d0
What is a complex ion
Consists of a central metal ion surrounded by ligands
When can cis and trans isomers occur in complex ions
- Octahedral complexes with 4 monodentate ligands of 1 type and 2 mondentate ligands of another type
- Square planar complexes woth 2 pairs of monodentate ligands
How is Hb an example of Ligand Subsitution
Central metal ion Fe2+ with 5 N co ordinate bonds and h2o gets replaced with either oxygen or carbon monoxide
What os euqstion for precipitation of M2+ with NaOH
[M(H2O)6]2+ + 2OH- -> M(H2O)4(OH)2 +2H20
What os euqstion for precipitation of M2+ with NH3 DROPWISE!!
[M(H20)6]2+ + 2NH3 -> M(H2O)4(OH)2 + 2NH4+
What color precp. does Fe2+ form with OH- / NH3
Green
What color precp. does Fe3++ form with OH- / NH3
Brown
What color precp. does Mn2++ form with OH- / NH3
Pale Brown
What color precp. does Cr3+ form with OH- / NH3
Dark green with OH AND EXCESS OH but purple with excess NH3
What is the interconversion of Fe2+
MnO4- + 8H+ + 5Fe2+ -> Mn2+ + 4H2O + 5Fe3+
2I- + 2Fe3+ -> 2Fe2+ + I2
What is the interconversion of Cr3+
3H2O2 + 2[Cr(OH)6]3- -> 2OH- + 2Cr2O42- + 8H2O
2Cr2O42- + 2H+ -> Cr2O72- + H2O
What is meant by a ligand
Donates lone pair of electrons and forms a co ordinate bond with a metal ion
What is meant by co ordination n.
N. of co ordiante bonds to metal ion
What is meant by ligand sub.
One ligand replacing another
What is the compound and colour formed when Cr3+ is oxidised v9ia H2O2
Cr2O4 2- and yellow colour forms
What colour forms when Cr2O7 2- is formed by additon of H2SO4
Orange colour
What is the colour change when Fe2+ is oxidised into Fe3+ by acidified potassium dichromate (KMNO4)
Pale green (Fe2+) to Yellow (Fe3+)
What is the reagnt used to convert Fe2+ into Fe3+
2I-
What is the reagent used to convert Fe3+ to Fe2+
MnO4-
What colour does copper form when chlroine/HCl is added
Yellow Solution
PRECIPITATE FOR SODIUM HYDROXIDE
SOLUTION WITH AMMONIA AND HCL
Why is, in the prescence of CO, less O2 is transported in the blood
K stab val. with CO is greater and Co oridnate bond with CO is stronger
