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PHAN111 > Finals T1: COMPLEXATION > Flashcards

Finals T1: COMPLEXATION Flashcards

1
Q

is the
process based on the formation of a complex substance in
the course of analysis.

A

Complexometry (complex-formation method)

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2
Q

use to detect elements like?

A

Calcium, copper, mercury, magnesium, zinc,aluminum and bismuth

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3
Q

will react with metal ions to form a water-soluble
stable complex or a chelate compound

or the common titrant in Complexometry

A

EDTA

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4
Q

EDTA chemical name

A

Ethylene diamine tetra acetic Acid

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5
Q

When a metal ion combines with a molecule which donate
electrons, the resulting compound is termed a _______?

A

Complex

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6
Q

If the combining molecule contains two or more groups that
donate electrons, this complex is called a ______

A

chelate

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7
Q

The groups bound to the central ion are called _______?

A

Ligands

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8
Q

Reason why Complexometric method is use?

A

Due to the formation of insoluble compounds, the complexometry is use to increase the solubility of the insoluble compound.

it also use to detect elements that causes hardness to the water.

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9
Q

Types of Ligands/ Chelating agent:

A

Ammonia (NH3)
Ethane-1,2-diamine (Edamine)
EDTA
1,4,7-triazaheptane (TACN)

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10
Q

measure of the strength of the
interaction between the reagents that come together to form the complex.

A

Stability constant

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11
Q

Stability constants should be greater than 8 = to ______

A

Increase complex formation

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12
Q

Element that forms very weak complex

A

Li (Lithium)
Na (Sodium)

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13
Q

Stability constants of an element that is below 8

A

Ag (Silver)
Ba (Barium)
K (Potassium)

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14
Q

an element that forms a colored metals

A

Fe (Iron)
Cu(Copper)

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15
Q

Stability constants (as log K) of
metal-EDTA complexes:
Mg2+: Magnesium

A

8.7

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16
Q

Stability constants (as log K) of
metal-EDTA complexes:
Ca2+: Calcium

A

10.7

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17
Q

Stability constants (as log K) of
metal-EDTA complexes:
Sr2+: Strontium

A

8.6

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18
Q

Stability constants (as log K) of
metal-EDTA complexes:
Ba 2+: Barium

A

7.8

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19
Q

Stability constants (as log K) of
metal-EDTA complexes:
Mn 2+ : Manganese

A

13.8

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21
Q

Stability constants (as log K) of
metal-EDTA complexes:
Fe 2+ : Iron II (Ferrous)

A

14.3

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21
Q

Stability constants (as log K) of
metal-EDTA complexes:
Co 2+ : Cobalt

A

16.3

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22
Q

Stability constants (as log K) of
metal-EDTA complexes:
Ni 2+: Nickel

A

18.6

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23
Q

Stability constants (as log K) of
metal-EDTA complexes:
Cu 2+: Copper

A

18.8

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24
Q

Stability constants (as log K) of
metal-EDTA complexes:
Zn 2+: Zinc

A

16.7

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25
Stability constants (as log K) of metal-EDTA complexes: Cd2+: Cadmium
16.6
26
Stability constants (as log K) of metal-EDTA complexes: Hg2+: Mercury
21.9
27
Stability constants (as log K) of metal-EDTA complexes: Pb2+: Lead
18.0
28
Stability constants (as log K) of metal-EDTA complexes: Al3+: aluminium
16.3
29
Stability constants (as log K) of metal-EDTA complexes: Fe 3+: Iron III (Ferric)
25.1
30
Stability constants (as log K) of metal-EDTA complexes: Y3+: Yttrium
18.2
31
Stability constants (as log K) of metal-EDTA complexes: Cr3+: Chromium
24.0
32
Stability constants (as log K) of metal-EDTA complexes: Na+: Sodium
1.7
33
Stability with respect to pH of some metal-EDTA complexes: Zr4+; Zirconium Hf4+; Hafnium Th4+; Thorium Bi3+; Bismuth Fe3+'; Ferric
pH 1-3
34
Stability with respect to pH of some metal-EDTA complexes: Pb2+; Lead Cu2+; Copper Zn2+; Zinc Co2+; Cobalt Ni2+; Nickel Mn2+; Manganese Fe2+; Ferrous Al3+; Aluminium Cd2+; Cadmium Sn2+; Tin
pH 4-6
35
Stability with respect to pH of some metal-EDTA complexes: Ca2+; Calcium Sr2+; Strontium Ba2+; Barium Mg2+; Magnesium
pH 8-10
36
Factors affecting EDTA reaction?
❖ Stability constant ❖ pH ( NaOH or ammonia-ammonium chloride buffer TS) Interfering ions (cyanide, citrate, tartrate, fluoride and other complex-forming agents) ❖ Neutral salts - NaCl
37
Interfering ions
cyanide, citrate, tartrate, fluoride and other complex-forming agents
38
organic compounds which form colored complex ions with metal ion in high dilutions.
Indicators
39
Qualities of a good indicator are:
❖ sharpness of color change at the endpoint ❖ specificity of the indicator for the metal ion under the conditions of the analysis ❖ stability constant smaller than that of the metal-EDTA complex –i.e. the indicator must give up the metal ion to the titrant EDTA for complexing and not compete with it.
40
Indicators: Complexometry
Eriochrome black, Dithiazone and Hydroxynaphthol blue.
41
The indicator used is hydroxynaphthol blue for ____ containing compounds. ( ______)
Calcium (1) Deep blue (2)
42
Standard Solution of complexometry?
EDTA – disodium EDTA solution 0.05M
43
Primary Standard for complexometry ?
calcium carbonate
44
compounds and their preparations requires Eriochrome black T.S. (_____)
Zinc (1) red to blue (2)
45
Common Indicator in coplexometry? (endpoint - appearance of a deep blue color) Hexadentate ligand
hydroxynaphthol blue
46
Inc EDTA stability constant can cause?
decrease of Indicator stability constant *this principle is the ideal proportion to have.
47
Used for assay Ca, Mg and Zn ❖ Calcium chloride ❖ Zinc sulfate ❖ Ca in water or water hardness what kind of assay they use?
Direct titration
48
Used for assay of Al, Bi compounds EDTA is determined using Metal-ion solution (Zinc sulfate) and stable indicator (dithiazone)
Residual Titration
49
metal ions(minerals) that are dissolved in the ground water can cause?
Hardness of water
50
Temporary hardness is cause by ?
Ca2+, Mg+2 carbonate
51
Temporary hardness can be reverse by?
Filtration and boiling the water simple process only
52
Permanent of water cause by the ?
sulfates and chlorides of calcium and magnesium in water.
53
Permanent of hardness can be reverse by?
the need of big machine and laboratory equipments
54
Concentration of Calcium Carbonate (mg/L): 0 to <75
Hardness of Water rating: Soft
55
Concentration of Calcium Carbonate (mg/L): 75 to <150
Hardness of Water rating: Medium hard
56
Concentration of Calcium Carbonate (mg/L): 150 to <300
Hardness of Water rating: hard
57
Concentration of Calcium Carbonate (mg/L): 300 and greater
Hardness of Water rating: Very hard
58
The term used to indicate the determination of a metal in the presence of another metal This may proceed by adjusting the pH or with the use of auxilliary complexing agents like
Masking
59
Zn-EDTA inactivates Hg, Cu, Bi
Masking: Thioglycols
60
imparts alkalinity Mg-EDTA over Al-EDTA Fe, Al,
Masking: TEA (triethanolamine)
61
mask the Zn, Co, Ni, Cu
masking: Potassium cyanide
62
masking – Mg, Al, Ca?
masking: Ammonium fluoride
63
In a solution containing the following metals: Magnesium, Zinc, Mercury, Aluminum and Copper: Which of these metals may form complex with EDTA if the above solution is treated with KCN (Potassium cyanide)?
II. Zn only
64
If the sample will be treated with triethanolamine, which of these metal/s will be precipitated?
IV. Al V. Mn
65
Which of these metals will form a stable complex with EDTA at pH of 4- 6?
V. Mn II. Zn IV. Al
66
Which of these metals will not form complex with thioglycol?
V. Mn IV. Al II. Zn I. Mg
67
Sodium Tetraphenylboron Titrations chemical name and concentration?
Na(C6H5)4B (freshly prepared,0.02M)
68
Sodium Tetraphenyl boron Titrations : INDICATOR
BPB (Bromophenol blue)
69
Sodium Tetraphenyl boron Titrations react on what compound?
Potassium dichromate by gravimetry
70
Sodium Tetraphenylboron Titrations: Extraction Indicator
Chloroform
71
protecting agent to protect amino acids. Organic nitrogen compounds ❖ Alkaloids, amines, quaternary amine salts, ammonium, potassium and silver ions
Sodium Tetraphenylboron
72
thioglycol chemical name ?
Di mercapto propanol

PHAN111 (9 decks)

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