Reactions of Transition Metal Ions in Solution

Question 1

Iron(II) Aqueous ion

Answer 1

[Fe(H2O)6]2+(aq)
green solution

Question 2

Iron(II) Action of NaOH

Answer 2

Fe(H2O)4(OH)2(s)
green ppt goes brown on standing in air

Question 3

Iron(II) Action of an excess of
NaOH(aq)

Answer 3

No further change

Question 4

Iron(II) Action of NH3(aq)

Answer 4

Fe(H2O)4(OH)2(s)
green ppt goes brown
on standing in air

Question 5

Iron(II) Action of an excess
of NH3(aq)

Answer 5

No further change

Question 6

Iron(II) Action of Na2CO3(aq)

Answer 6

FeCO3(s)
green ppt

Question 7

Copper(II) Aqueous ion

Answer 7

[Cu(H2O)6]2+(aq)
blue solution

Question 8

Copper(II) Action of NaOH

Answer 8

Cu(H2O)4(OH)2(s)
blue ppt

Question 9

Copper(II) Action of an excess of NaOH(aq)

Answer 9

No further change

Question 10

Copper(II) Action of NH3(aq)

Answer 10

Cu(H2O)4(OH)2(s)
blue ppt

Question 11

Copper(II) Action of an excess of NH3(aq)

Answer 11

[Cu(H2O)2(NH3)4]2+(aq)
deep blue solution

Question 12

Copper(II) Action of
Na2CO3(aq)

Answer 12

CuCO3(s)
blue-green ppt

Question 13

Iron(III) Aqueous ion

Answer 13

[Fe(H2O)6]3+(aq)
purple solution may look yellow-brown due to some [Fe(H2O)5(OH)]2+(aq)

Question 14

Iron(III) Action of NaOH

Answer 14

Fe(H2O)3(OH)3(s)
brown ppt
(ppt may look orange-brown)

Question 15

Iron(III) Action of an excess of NaOH(aq)

Answer 15

No further change

Question 16

Iron(III) Action of NH3(aq)

Answer 16

Fe(H2O)3(OH)3(s)
brown ppt
(ppt may look orangebrown)

Question 17

Iron(III) Action of an excess of NH3(aq)

Answer 17

No further change

Question 18

Iron(III) Action of Na2CO3(aq)

Answer 18

Fe(H2O)3(OH)3(s)
brown ppt
(ppt may look orange-brown)
and CO2 gas evolved

Question 19

Aluminium(III) Aqueous ion

Answer 19

[Al(H2O)6]3+(aq)
colourless solution

Question 20

Aluminium(III) Action of NaOH

Answer 20

Al(H2O)3(OH)3(s)
white ppt

Question 21

Aluminium(III) Action of an
excess of NaOH(aq)

Answer 21

[Al(OH)4]–(aq)
colourless solution

Question 22

Aluminium(III) Action of NH3(aq)

Answer 22

Al(H2O)3(OH)3(s)
white ppt

Question 23

Aluminium(III) Action of an excess of NH3(aq)

Answer 23

No further change

Question 24

Aluminium(III) Action of
Na2CO3(aq)

Answer 24

Al(H2O)3(OH)3(s)
white ppt and CO2 gas evolved

Question 25

V(V) Species in acidic solution and colour of solution

Answer 25

[VO2(H2O)4]+ yellow

Question 26

V(IV) Species in acidic solution and colour of solution

Answer 26

[VO(H2O)5]2+ blue

Question 27

V(III) Species in acidic solution and colour of solution

Answer 27

[V(H2O)6]3+ green

Question 28

V(II) Species in acidic solution and colour of solution

Answer 28

[V(H2O)6]2+ purple

Question 29

what are transition metals and its properties

Answer 29

metals that form one or more stable ions with a partially filled d subshell -form complexes -form coloured ions -have variable oxidation states -are good catalysts

Question 30

what is a complex

Answer 30

central metal atom or ion surrounded by ligands

Question 31

what is a ligand

Answer 31

molecule or ion that joins to a central transition metal atom or ion via a co ordinate bond by donating a pair of electrons

Question 32

what is a coordintation number

Answer 32

the number of coordinate bonds to the central metal atom or ion

Question 33

monodentate, bidentate, polydentate ligand

Answer 33

mono- ligand donates one pair poly- 2 or more pairs bi- 2 pairs

Question 34

examples of monodentate ligands

Answer 34

Cl-, CN- NH3 and H2O

Question 35

examples of bidentate ligands

Answer 35

C2O4^2- NH2CH2CH2NH2

Question 36

example of a hexadentate ligand

Answer 36

EDTA^4-

Question 37

what is coordination number affected by

Answer 37

-size of metal ion and ligands -electronic configuration of metal ion

Question 38

why do transition metal ions appear coloured

Answer 38

they absorb certain frequencies of light causing electrons in d sub-shell to become excited the colour observed is the light not absorbed/the light transmitted

Question 39

what factors affect the size of the energy gap between d block compounds

Answer 39

-transition metal ion -oxidation state -ligands -shape

Question 40

how to calculate energy difference

Answer 40

energy= planck x frequency velocity of light= wavelength x frequency therefore, energy= (planck x velocity) / wavelength

Question 41

how to find conc of unknown solution

Answer 41

-make up standard solutions of coloured compounds -choose suitable filter -zero the colorimeter with tube of pure solvent -measure absorbance of standard solutions and plot calibration curve -measure absorbance of unknown solution and read off conc from calibration curve

Question 42

redox of MnO4^-, Fe^2+ and C2O4^2-

Answer 42

MnO4^- --> Mn^2+ Fe^2+ --> Fe^3+ C2O4^2- --> CO2

Question 43

what is a homogenous catalyst

Answer 43

-catalyst in the same phase as the reactants -forms an intermediate compound -intermediate breaks down to form product and catalyst reforms

Question 44

show how Fe2+ acts as a catalyst for S2O8^2- to SO4^2-

Answer 44

slow reaction because negative ions repel S2O8^2- + 2Fe^2+ --> 2SO4^2- + 2Fe^3+ (intermediate) 2Fe^3+ + 2I- --> I2 + 2Fe2+

Question 45

what is a heterogenous catalyst and how does it work

Answer 45

catalyst in a different phase from the reactants -reactants adsorb onto surface of catalyst -the bonds in the reactant are weakened -products desorb from catalyst surface

Question 46

what is catalyst poisoning

Answer 46

-if the bonds are too strong, the products may remain fixed to the catalyst -active sites blocked

Question 47

what are the stages of the contact process used to make sulfuric acid

Answer 47

S + O2 --> SO2 2SO2 + O2 <--> 2SO3 SO3 + H2O --> H2SO4

Question 48

what are the equations for the contact process with a vanadium oxide catalyst

Answer 48

V2O5 + SO2 --> V2O4 + SO3 2V2O4 + O2 --> 2V2O5

Question 49

what does the graph for autocatalysis look like

Answer 49

-starts slowly as not much catalyst product has formed -slope increases as catalyst forms -slope decreases as reactants are being used up

Question 50

why are aqua ions with a 3+ charge more acidic than those with a 2+ charge

Answer 50

3+ ions have a higher charge density so the OH bond is weakened tendency to donate a H+ ions increases making the solution acidic

Question 51

overall equation of reacting [M(H2O)6]3+ with XS OH-

Answer 51

[M(H2O)6]3+ + 3OH- --> M(H2O)3(OH)3 + 3H2O

Question 52

overall equation of reacting [M(H2O)6]2+ with XS OH-

Answer 52

[M(H2O)6]2+ +2OH- --> M(H2O)4(OH)2 +2H2O

Question 53

[M(H2O)6]3+ with NH3

Answer 53

[M(H2O)6]3+ + 3NH3 --> M(H2O)3(OH)3 + 3NH4+

Question 54

[M(H2O)6]2+ with NH3

Answer 54

[M(H2O)6]2+ +2NH3 --> M(H2O)4(OH)2 + 2NH4+

Question 55

reaction of Cu(H2O)4(OH)2 with XS NH3

Answer 55

[Cu(H2O)6]2+ + 4NH3 --> [Cu(NH3)4(H2O)2]2+ + 2H2O + 2OH-

Question 56

[M(H2O)6]3+ with CO3^2-

Answer 56

2[M(H2O)6]3+ + 3CO3^2- --> 2M(H2O)3(OH)3 + 3CO2 + 3H2O

Question 57

[M(H2O)6]2+ with CO3^2-

Answer 57

[M(H2O)6]2+ + CO3^2- --> MCO3 + 6H2O

Question 58

reactions of Al(H2O)3(OH)3 with acid and base

Answer 58

Al(H2O)3(OH)3 + H+ --> [Al(H2O)6]3+ Al(H2O)3(OH)3 + OH- --> [Al(OH)4]- + 3H2O

Question 59

[M(H2O)6]2+ with H2O

Answer 59

[M(H2O)6]3+ + H2O --> [M(OH)(H2O)5]+ + H3O+

Question 60

[M(H2O)6]3+ + H2O

Answer 60

[M(H2O)6]3+ + H2O --> [M(OH)(H2O)5]2+ + H3O+