Complexometry Flashcards

1
Q

Formation of complexes
Method of choice for polyvalent metal ions

A

Complexometry/Complexation Method

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2
Q

A molecule which provides groups of attachment to metal ion

A

Ligand

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3
Q

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

A

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

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4
Q

Bind to a metal ion through 1 atom

A

Monodentate Ligand

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5
Q

Binds to metal ion through more than 1 group

A

Multidentate Ligand

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6
Q

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

A

Complex

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7
Q

Complex formed between a ligand and metal ions

A

Chelate

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8
Q

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

A

Chelates

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9
Q

The formation of a stable, soluble complex

A

Driving force

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10
Q

Solubility Constant aka

A

Formation Constant

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11
Q

Application of the law of mass action to the reaction equilibrium

A

Solubility Constant

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12
Q

Volumetric Solution used in Complexation Method

A

EDTA (Hexadentate ligand)

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13
Q

Standard solution used in Complexation Method

A

Calcium carbonate

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14
Q

Indicator used in Complexation Method

A

Metal Ions Indicators

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15
Q

Complexation Method is used for assay of

A

Mg, Ca, Zn, Al, Bi

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16
Q

Direct Titration in Complexometry

A

Mg, Ca, Zn

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17
Q

Residual Titration in Complexometry

A

Al, Bi

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18
Q

EDTA

A

Ethylenediaminetetraacetic acid

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19
Q

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

A

EDTA

20
Q

How many bonds or attachment can EDTA form with a metal

A

Six (Hexadentate Ligand)

21
Q

EDTA is made up of

A

4 Oxygen
2 Nitrogen

22
Q

Factors influencing EDTA Reactions

A

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)

23
Q

Standardization of EDTA can be done by addition of

A

Hydrochloric Acid
Sodium Hydroxide

24
Q

Addition of Hydrocholoric Acid in EDTA result to

A

Solubilizes calcium carbonate by converting it to Calcium chloride

25
Q

Addition of NaOH to EDTA

A

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

26
Q

Endpoint of EDTA Standardization

A

Blue

27
Q

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

A

Masking

28
Q

Detection of metal in presence of other metals

A

Masking

29
Q

Masking is done by

A

Adjusting pH of titration medium
Use of Masking Agents
Precipitation

30
Q

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

A

Masking Agents

31
Q

Masking Agents

A

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

32
Q

Elements masked by Triethanolamine

A

Mn, Al, Fe

33
Q

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

A

Hg, Cu, Bi, Cd, Pb

34
Q

Elements masked by Potassium cyanide

A

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

35
Q

Elements masked by Ammonium fluoride

A

Mg, Al, Ca, Be

36
Q

Removal of masking agent from species protected by the masking agent

A

Demasking

37
Q

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

A

Demasking

38
Q

Demasking releases the ______ from ______

A

Demasking releases the metal ion from masking agent

39
Q

Prevent metal ion from precipitating in the absence of EDTA

A

Auxilliary/Complexing Agent

40
Q

Compounds that change color when bind to a metal ion

A

Metal Ion Indicators

41
Q

Metail Ion Indicators

A

CHEMP XD

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

42
Q

Metal Ion indicator used for the assay of Calcium

A

Hydroxynaphthol Blue

43
Q

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

A

Eirochrome Black T

44
Q

Metal Ion indicator used for the assay of Al, Bi

A

Dithizone

45
Q

Result of Calcium assay

A

Blue

46
Q

Result of Bi, Mg, Zn assay

A

Blue

47
Q

Result of Al, Bi assay

A

Pink