Complexometry

Question 1

Formation of complexes
Method of choice for polyvalent metal ions

Answer 1

Complexometry/Complexation Method

Question 2

A molecule which provides groups of attachment to metal ion

Answer 2

Ligand

Question 3

Ligand contains at least one group which _____ electrons to combine with ________

Answer 3

Ligand contains at least one group which DONATES electrons to combine with METAL IONS

Question 4

Bind to a metal ion through 1 atom

Answer 4

Monodentate Ligand

Question 5

Binds to metal ion through more than 1 group

Answer 5

Multidentate Ligand

Question 6

The resulting compound when a metal ion combines with a moledcule which contains 1 group that donate electrons (Ligand)

Answer 6

Complex

Question 7

Complex formed between a ligand and metal ions

Answer 7

Chelate

Question 8

Formed when a metal ion combines with molecule with >2 groups that donate electrons

Answer 8

Chelates

Question 9

The formation of a stable, soluble complex

Answer 9

Driving force

Question 10

Solubility Constant aka

Answer 10

Formation Constant

Question 11

Application of the law of mass action to the reaction equilibrium

Answer 11

Solubility Constant

Question 12

Volumetric Solution used in Complexation Method

Answer 12

EDTA (Hexadentate ligand)

Question 13

Standard solution used in Complexation Method

Answer 13

Calcium carbonate

Question 14

Indicator used in Complexation Method

Answer 14

Metal Ions Indicators

Question 15

Complexation Method is used for assay of

Answer 15

Mg, Ca, Zn, Al, Bi

Question 16

Direct Titration in Complexometry

Answer 16

Mg, Ca, Zn

Question 17

Residual Titration in Complexometry

Answer 17

Al, Bi

Question 18

EDTA

Answer 18

Ethylenediaminetetraacetic acid

Question 19

React with metal ions to form water-soluble, stable complex/chelate compounds

Answer 19

EDTA

Question 20

How many bonds or attachment can EDTA form with a metal

Answer 20

Six (Hexadentate Ligand)

Question 21

EDTA is made up of

Answer 21

4 Oxygen
2 Nitrogen

Question 22

Factors influencing EDTA Reactions

Answer 22

Metal ion activity
pH at w/c titration run (↑ stability constant, ↑ pH)
Presence of interfering ions (Cyanide, Citrate, Tartrate, Fuorides)
Organic solvents (↑ stability of complex)
Neutral salts such as NaCl (↓ stability)

Question 23

Standardization of EDTA can be done by addition of

Answer 23

Hydrochloric Acid
Sodium Hydroxide

Question 24

Addition of Hydrocholoric Acid in EDTA result to

Answer 24

Solubilizes calcium carbonate by converting it to Calcium chloride

Question 25

Addition of NaOH to EDTA

Answer 25

Alkalinizes the solution to pH 13 Ca-EDTA complex stability No reaction to Mg

Question 26

Endpoint of EDTA Standardization

Answer 26

Blue

Question 27

Addition of a substance to a sample to prevent reacting in a chemical analysis

Answer 27

Masking

Question 28

Detection of metal in presence of other metals

Answer 28

Masking

Question 29

Masking is done by

Answer 29

Adjusting pH of titration medium Use of Masking Agents Precipitation

Question 30

Reagent that selectively reacts with one components of a solution to prevent the components from interfering in a chemical analysis

Answer 30

Masking Agents

Question 31

Masking Agents

Answer 31

Triethanolamine Thioglycol (aka: 2,3-dimercaptopropanol) Potassium Cyanide Ammonium fluoride

Question 32

Elements masked by Triethanolamine

Answer 32

Mn, Al, Fe

Question 33

Elements masked by Thioglycol (aka: 2,3-dimercaptopropanol)

Answer 33

Hg, Cu, Bi, Cd, Pb

Question 34

Elements masked by Potassium cyanide

Answer 34

Cu, Zn, Co, Ni, Hg Hg2+, Ad, Pd, Pt, Fe2+, Fe3+

Question 35

Elements masked by Ammonium fluoride

Answer 35

Mg, Al, Ca, Be

Question 36

Removal of masking agent from species protected by the masking agent

Answer 36

Demasking

Question 37

The masked substance regains its ability to enter into a particular reaction

Answer 37

Demasking

Question 38

Demasking releases the ______ from ______

Answer 38

Demasking releases the metal ion from masking agent

Question 39

Prevent metal ion from precipitating in the absence of EDTA

Answer 39

Auxilliary/Complexing Agent

Question 40

Compounds that change color when bind to a metal ion

Answer 40

Metal Ion Indicators

Question 41

Metail Ion Indicators

Answer 41

CHEMP XD Calmagite Hydroxynaphtol Blue Eirochorme Black T Murexide Pyrocathechol violet Xylenol Orange Dithizone

Question 42

Metal Ion indicator used for the assay of Calcium

Answer 42

Hydroxynaphthol Blue

Question 43

Metal Ion indicator used for the assay of Bi, Mg, Zn

Answer 43

Eirochrome Black T

Question 44

Metal Ion indicator used for the assay of Al, Bi

Answer 44

Dithizone

Question 45

Result of Calcium assay

Answer 45

Blue

Question 46

Result of Bi, Mg, Zn assay

Answer 46

Blue

Question 47

Result of Al, Bi assay

Answer 47

Pink