M Lesson 3: Complexation Titrations

Question 1

These are class of reactions that deal with complex formation

Answer 1

Complexation Methods

Question 2

Current method of choice for the determination of metal ions except
Group ____ metals

Answer 2

Complexation Methods; 1A

Question 3

During titration, metal ion reacts with a suitable _______ to form a complex

Answer 3

ligand

Question 4

The equivalence point is determined by an __________ or appropriate instrumental method

Answer 4

Indicator

Question 5

Titrant of CT

Answer 5

Chelating Agent/Complexing Agent/complexone

Question 6

Analyte of CT

Answer 6

Metals

Question 7

Product of CT

Answer 7

Metal-Chelate (EDTA) complex

Question 8

Na2EDTA (chelating agent/titrant) acts as

Answer 8

Lewis Base

Question 9

What happens during complex formation?

Answer 9

A metal ion combines with a compound-donating electron

Question 10

A chemical species containing a central metal ion bonded to one or more ligands

Answer 10

Complex

Question 11

Complex is less stable than chelates. T or F?

Answer 11

True!

Question 12

In a _______, ligands bind to the metal ion through a variety of coordination modes like monodentate, bidentate, pooydentate

Answer 12

Complex

Question 13

A _______ is a type of complex where the ligands form a cyclic structure around the metal ion

Answer 13

Chelate

Question 14

Chelate is more stable than complexes. T or F?

Answer 14

True!

Question 15

______ ligands are specifically designed to bind to the metal ion through multiple coordination sites, forming a cyclic structure

Answer 15

Chelate

Question 16

What is the most commonly used analytical reagent for Complexation Titrations?

Answer 16

Disodium EthyleneDiamineTetraAcetate (Na2EDTA)

Question 17

NA2 EDTA stands for

Answer 17

Disodium EthyleneDiamineTetraAcetate

Question 18

Octadentates (such as DTPA) give more stable complexes than hexadentates (EDTA). T or F?

Answer 18

True!

Question 19

EDTA has the widest general application in the analysis because of its

Answer 19

powerful complexing action and commercial availability

Question 20

Factors affecting the stability of complex

Answer 20

1. Number of dentates
2. Temperature
3. pH
4. Stability constant (kf) value

Question 21

Some metal EDTAs are more stable at _____ temperatures

Answer 21

Higher

Question 22

EDTA forms more stable complexes at _______ pH levels

Answer 22

Higher

Question 23

EDTA has how many acidic protons that dissociate based on pH and what are those

Answer 23

4 ; write the 4 on a piece of paper and check it on the index card

Question 24

What is the most effective form of EDTA?

Answer 24

HY3- <-> H+ + Y4-

Question 25

The proportion of each form of EDTA, depends on ___

Answer 25

pH

Question 26

At ___ pH, EDTA remains _____ and can’t bind metal ions

Answer 26

Low; protonated

Question 27

At _____ pH, more EDTA is in the ________ form, which enhances metal binding

Answer 27

High; effective Y4-

Question 28

If the solution is too _____, metal EDTA complexes may not form properly because Y4- is not available

Answer 28

Acidic

Question 29

If the solution is too ______, some metals may precipitate as hydroxides, interfering with titration

Answer 29

Basic

Question 30

EDTA titrations require _______ _______ to maintain the correct pH

Answer 30

Buffer solutions

Question 31

The choice of buffer depends on the _____ ___ being analyzed

Answer 31

Metal ion

Question 32

Y4- represents what?

Answer 32

the fully deprotonated form of EDTA (ion)

Question 33

Mn+ represents what?

Answer 33

The metal ion in solution

Question 34

MY^n-4 represents what?

Answer 34

is the stable metal-EDTA complex that forms during titration

Question 35

determines how stable a metal-EDTA complex is

Answer 35

Formation constant (Kf)

Question 36

______ Kf values mean stronger, more stable complexes

Answer 36

Higher

Question 37

For an EDTA titration to be successful, kf must be

Answer 37

Greater than 8

Question 38

In EDTA titrations, the__________ _________ forms complexes with metal ions

Answer 38

Unprotonated ligand, Y4-

Question 39

Organic compounds which form colored complex ions with metal ion. FQ : Where?

Answer 39

Merallochromicnindicators ( in high dilution

Question 40

Molecule which donates electrons

Answer 40

Ligand

Question 41

Is a species that has a molecule with at least one pair of unshared electrons

Answer 41

Ligand

Question 42

Complexing agent

Answer 42

Ligand

Question 43

If I can contains two or more molecules that can donate electrons the resulting group is a

Answer 43

Chelate

Question 44

Most common indicators

Answer 44

Dithizone (Zn) Eriochrome black t (Mg) Hydroxynaphthol blue (Ca) + Solochrome black

Question 45

Qualities of a good indicator

Answer 45

Gives sharp endpoint Specific foe a certain metal bing analyzed Kf is lower than the kf of metal edta complex

Question 46

Metallichromic indicators react forst with the _____________

Answer 46

Metal ion being analyzed

Question 47

Substance analyzed in complexometry

Answer 47

Divalent or polyvalent

Question 48

Most common VS

Answer 48

EDTA VS and Zn Sulfate VS

Question 49

Zinc sulfate VS for

Answer 49

Residual titration

Question 50

Technique used to indicate the determination of a metal in the presence of another metal

Answer 50

Masking

Question 51

Too much indicator should be avoided because many indicators exhibits

Answer 51

Dichroism

Question 53

Masking is done by adding ____

Answer 53

Masking agent

Question 54

A compound capable of forming a complexation reaction at a favorable pH condition

Answer 54

Masking agent