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PHAN111 > Non – Aqueous Titration & KJELDAHL Method > Flashcards

Non – Aqueous Titration & KJELDAHL Method Flashcards

1
Q

3 reason why Non – Aqueous Titration use

A
  • Most organic acids and bases are insoluble in water
    ❖ Most organic acids and bases are weak acids and bases
    ❖ Moisture must be avoided or at least limited to 0.05%
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2
Q

Non – Aqueous Titration: Acid titrant

A

Perchloric acid in glacial acetic acid or dioxane

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3
Q

Non – Aqueous Titration: Base titrant

A

Sodium methoxide,
Lithium methoxide in
ethylenediamine, n-butylamine, morpholine

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4
Q

Non – Aqueous Titration: Indicators
ACIDIMETRY - Weak bases

A

common: Crystal violet
malachite green,
quinaldine red,
methylrosaniline

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5
Q

Non – Aqueous Titration: Indicators
ACIDIMETRY - (relatively stronger base)

A

Methyl orange, methyl red, Thymol blue

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6
Q

Non – Aqueous Titration: Indicators
ALKALIMETRY - (weak acids)

A

Azoviolet

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7
Q

Non – Aqueous Titration: Indicators
ALKALIMETRY - (strong acids)

A

Thymol blue

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8
Q

Non – Aqueous Titration: Indicators
ALKALIMETRY - (most preferred)

A

potentiometric methods

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9
Q

A method designed to determine and quantify ammonia in
ammonium sulfate obtained by decomposing organic
substance with sulfuric acid

Nitrogen determination

A

KJELDAHL Method

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10
Q

Standardization in Non-aqueous titration: __________ + Perchloric acid —->__________+_______

A

1: Potassium Hydrogen Phthalate
2: Phthalic acid
3: Potassium Chlorate

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11
Q

KJELDAHL Method: standard sol- H2SO4
Sx + H2SO4 (CUSO4, Se) —> (NH4)SO4 + H2O
formation of Ammonium Sulfate
What step is this ?

A

Step 1: Digestion

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12
Q

KJELDAHL Method: standard sol- NaOH
(NH4)SO4 + NaOH—> NH3 + Na2SO4 + H2O
formation of Ammonia
What step is this?

A

Step 2: Neutralization

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13
Q

KJELDAHL Method: standard sol- H3BO3 (boric acid)
NH3 + H3BO3—–> (NH4)2B4O7+H2O
formation of Diammonium Tetraborate
What step is this?

A

Step 3: Distillation

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14
Q

KJELDAHL Method: standard sol- HCl
(NH4)2B4O7+HCl —-> (NH4)Cl + H3BO3
formation of Ammonium chloride
What step is this?

A

Step 4: Titration

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15
Q

if N is as NO3, _______ is add

A

salicylic acid

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16
Q
  • USP Methods
  • Method I for ________
  • Method II for _______
A

macroanalysis (1)
semimicroanalysis (2)

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17
Q

Kjeldahl set-up

A

heater
Digestion flask (step 1)
Trap [digestion of sample nitrogen converted to ammonia]
Condenser [Distillation of ammonia into a trapping solution]
trapping flask [quantification of the ammonia by titration w/ a standard solution]

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18
Q

% sample = (ml x N) acid - (ml x N) base x meq sample
—————————————— x 100
wt of sample

A

formula for – Acidimetric assay, Nitrogen determination

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19
Q

Nitrogen determination use in ?

A

Protein in food, fertilizer, blood, assays of Heparin,
insulin, urea, povidone

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20
Q

Urea properties:

A

CO(NH2)2
60.06 g/mol
factor : 2

21
Q

Precipitation Method is Also called?

A

Argentometric titration

22
Q

Volumetric methods based on
reactions that yield ionic
compounds of limited
solubility

A

Argentometric titration

23
Q

primary analyte use to find Argentometric titration is ???

A

Chlorine/ Halides

24
Q

Common titrant use in Argentometric titration?

A

Silver Nitrate

25
other name of Silver Nitrate
AgNO3 Lapiz infernulariz indelible ink caustic pencil Lunar pencil
26
Old medical use of silver nitrate?
neonatal conjunctivitis
27
recent treatment for neonatal conjunctivitis?
crede's prophylaxis
28
crede's prophylaxis is a combination of what drug?
Erythromycin + Tetracycline
29
neonatal conjunctivitis is caused by what kind of bacteria?
Neisseria Gonorrhea
30
3 ADSORPTION INIDICATOR
DCF: Dichlorofluorescein Eosin Y: Tetrabromofluorescein TEE: tetrabromophenolphthalein ethyl
31
types of indicator: takes part in chemical reaction ? and commonly use in precipitation
Internal indicator
32
types of indicator: did not take part in the chemical reaction and commonly use in neutralization
External Indicator
33
what indicator is use in redox method ex: KMnO4
self indicating indicator
34
formation of insoluble colored complex slight excess thiocyanate ion reacts with ferric ion from the indicator producing a faint reddish brown coloration * use HNO3 to acidify the analyte
Volhard Method
35
Volhard Method: Volumetric precipitation table
1st std : Silver nitrate VS (2nd std): ammonium thiocyanate indicator: Ferric Alum -(Fe(NH4)(SO4)2 example: Aminophylline NaCl end point: faint reddish brown FeNH4(SO4)2+ 3NH4SCN Fe(SCN)3 ↓+ 2(NH4)2S
36
Formation of 2nd precipitate chromate reacts with excess silver ions forming a secondary precipitate of reddish silver chromate INC Base of the analyte it use " CaCO3 and NaHCO3" INC Acid of the analyte it use CH3COOH
Mohr Method
37
Mohr Method: Volumetric precipitation table
1st std : Sodium Chloride (NaCl) VS (2nd std): Silver nitrate indicator: Potassium chromate (K2CrO) example: SLS end point: reddish silver chromate AgNO3 + K2CrO4 à AgCrO4 ↓+ KNO
38
COLORED ADSORPTION PRODUCT change in color precipitate. used as indicator in the titration of potassium chloride with standard silver nitrate solution. ❖ silver chloride (ppt)formed is negatively charged due to adsorbed chloride ion and the indicator exists in the solution with a greenish yellow ❖ Direct titration with silver nitrate solution slight excess of silver ion is adsorbed by the silver chloride precipitate colloid particles became positively charged which adsorb the fluoresceinate ions forming a reddish pink adsorption product
Fajan Method
39
Fajan Method: Volumetric precipitation table
1st std : Sodium Chloride (NaCl) VS (2nd std): Silver nitrate indicator: DCF, Eosin Y, TEE example: Phenylephrine HCl and Tubocuraine end point: reddish pink
40
Gay-Lussac: Volumetric precipitation table
1st std : Sodium Chloride (NaCl) VS (2nd std): Silver nitrate indicator: None example: NaCl cessation of precipitation
41
Liebig: Volumetric precipitation table
1st std : potassium biphthalate VS (2nd std): Sodium tetraphenyl Boron indicator: Bromophenol blue example: Organic N Compounds appearance of turbidity.
42
neonatal conjunctivitis is also called ?
ophthalmia neonatorum
43
USP requirements of Ammonium Bromide?
99.5% - 100.5%
44
USP requirements of Zinc Oxide?
95% - 98%
45
USP requirements of acetic acid?
2%-5%
46
factor of AgBr, KBr, BaCl2, Hg?
AgBr: 1 KBr: 1 BaCl2: 2 Hg: 2
47
Substances assayed: mainly used for determination of __________and some compounds that form insoluble products (ppt) with AgNO3
halides (Cl-, Br- & I-), SCN-(thiocyanate), CN- Cyanide Heavy Metals: Hg
48
Primary standard of Precipitation Assay?
sodium chloride
49
Standardization of ____Silver nitrate (concentration)
0.1 Normality

PHAN111 (9 decks)

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