Complex Formation Titration

Question 1

These are formed when metal ions react with a ligand.

Answer 1

complexes or coordination compounds

Question 2

These are ions or molecules that have a pair of unshared electrons capable of satisfying the coordination number of the cation

Answer 2

ligands

Question 3

The amount of covalent bonds a cation form is dictated by the?

Answer 3

coordination number

Question 3

Ligands are ions or molecules that have a pair of unshared electrons capable of satisfying the ________________________ of the cation.

Answer 3

coordination number

Question 4

typical value of coordination number?

Answer 4

two, four, six

Question 4

types of ligand

Answer 4

1. monodentate
2. bidentate
3. polydentate

Question 5

Titrations based on complex formation, sometimes called?

Answer 5

complexometric titrations

Question 6

examples of monodentate ligand

Answer 6

• water
• ammonia
• fluoride ion
• chloride ion
• cyanide ion
• thiocyanate ion
• hydroiodide ion
• nitrite ion

Question 7

examples of polydentate ligand

Answer 7

• diethylenetriamine
• triphosphate ion
• ethylenediaminetetraacetate ion

Question 7

examples of bidentate ligand

Answer 7

• ethylenediamine (en)
• bipyridine
• ortho-phenanthroline
• oxalate ion
• carbonate ion

Question 8

Formation of [Cu(NH3)4]2+ complex occur in a?

Answer 8

stepwise function

Question 9

For any equilibrium, the larger the value of the _______________________, the more stable the product.

Answer 9

equilibrium constant

Question 9

Equilibrium constant for complex formation is called?

Answer 9

formation constant (Kf)

Question 10

Most ____________________ do not have an easily identifiable end point

Answer 10

unidentate ligands

Question 11

_________________ ligands provide sharper end point.

Answer 11

polydentate

Question 12

Contain two or more atoms that can simultaneously coordinate to a central metal ion, occupying two or more coordination spheres.

Answer 12

polydentate ligands

Question 12

Chelating agents

Answer 12

polydentate ligands

Question 13

Because of the multiple bonding site, these ligands react strongly with cations, thus providing sharper end points.

Answer 13

polydentate ligands

Question 14

This is a hexadentate ligand with six binding sites, four negatively charged oxygen atoms in the carboxylate groups and two nitrogen atoms in the tertiary amino groups

Answer 14

Ethylenediaminetetraacetic acid (EDTA)

Question 15

1st and 2nd dissociation

Answer 15

carboxylic group

Question 16

3rd and 4th dissociation

Answer 16

removal of hydrogen from the amine group.

Question 17

All metal–EDTA complexes have a _________ stoichiometry

Answer 17

1:1

Question 18

name of the product of two constants

Answer 18

conditional formation constant

Question 19

The conditional formation constant is dependent on the ______________.

Answer 19

pH of solution

Question 20

it is dependent on the pH of solution

Answer 20

conditional formation constant

Question 21

classification of EDTA titration techniques

Answer 21

• direct titration
• back titration
• displacement titration
• indirect titration

Question 22

In __________________ you simply add an indicator to a buffered solution of the metal ion and titrate with standard EDTA.

Answer 22

direct titrations

Question 23

In a ________________, an excess of EDTA is added to the sample solution containing an analyte metal ion.

Answer 23

back titration

Question 24

This is useful when the analyte metal ion binds the indicator permanently, when the metal-EDTA complex is unstable, or when the metal ions form precipitates in the without EDTA.

Answer 24

back titration

Question 25

It can be used if the analyte metal ions do not have a good indicator. In this case, a metal ion-EDTA complex is added.

Answer 25

Displacement titration

Question 25

It is useful for anions which for insoluble precipitates like sulfate. Sulfate can be reacted with known amounts of Barium chloride.

Answer 25

Indirect Titration

Question 26

The precipitate BaSO4 is ________________, and the remaining solution is ______________ with standard EDTA solution.

Answer 26

filtered, titrated

Question 27

This is the most common type of EDTA titration

Answer 27

direct titration