Precipitation Flashcards

1
Q

Precipitation Method is also called ?

A

Argentometric Titration

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2
Q

Volumetric methods based on reactions that yield ionic COMPOUNDS OF LIMITED SOLUBILITY.

A

Precipitation Method

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3
Q

Analyte is titrated with a _____________________________ in the presence of a suitable indicator.

A

standard solution of a precipitating agent

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4
Q

Precipitation Method applies the _______________ principle.

A

solubility product

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5
Q

States that in a saturated solution of an ionic compound, the product of the molar activities (Ksp), has a constant value at any particular temperature and pressure.

A

Solubility Product Principle

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6
Q

Ksp meaning

A

Solubility Product Constant

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7
Q

Determined by

❖ Cessation of precipitation or appearance of turbidity
❖ Instrumental methods (potentiometry)
❖ Use of internal indicators

A

Endpoint

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8
Q

Potentiometry has?

A

Electrodes

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9
Q

Indicators

A

Colored lon - Volhard Method (Jacob Volhard)

Colored precipitate - Mohr Method (Karl Friedrich Mohr)

Colored Adsorption product - Fajan Method (Kazimiers Fajan)

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10
Q

Colored Ion

A

Volhard Method (Jacob Volhard)

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11
Q

Colored Precipitate

A

Mohr Method (Karl Friedrich Mohr)

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12
Q

Colored Adsorption Product

A

Fajan Method (Kazimiers Fajan)

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13
Q

Indicator used in Volhard’s Method

A

Ferric alum TS

(ferric ammonium sulfate, FeNH4(SO4)2)

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14
Q

Arrow up

A

Evolution of gas

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15
Q

Arrow down

A

Precipitation

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16
Q

In colored ion,

Slight excess thiocyanate ion reacts with ferric ion from the indicator producing a ________________ coloration.

A

faint reddish brown

17
Q

Used in thiocyanate titrations.

A

Colored Ion

18
Q

Indicator used in Colored Secondary Precipitate

A

Potassium chromate solution (Kr2CO4)

19
Q

In colored secondary precipitate,

Chromate reacts with excess silver ions forming a secondary precipitate of _______ silver chromate.

20
Q

Used in the titration of halides with standard silver nitrate solution.

A

Colored Secondary Precipitate

21
Q

Indicator used in Fajan Method

A

• Dichlorofluorescein
• Eosin Y (Tetrabromofluorescein)
• TEE - fluorescence (Tetrabromophenolphthalein ethyl ester)

22
Q

Eosin Y chemical name

A

Tetrabromofluorescein

23
Q

TEE - fluorescence other name

A

Tetrabromophenolphthalein ethyl ester

24
Q

Used as indicator in the titration of potassium chloride with standard silver nitrate solution.

A

Colored Adsorption Product

25
In colored adsorption product, Silver chloride (ppt) formed is negatively charged due to adsorbed chloride ion and the indicator exists in the solution with a ______________.
greenish yellow
26
Direct titration with silver nitrate.
Colored Adsorption Product
27
In colored adsorption product, slight excess of silver ion is adsorbed by the silver chloride precipitate colloid particles became positively charged which adsorb the fluoresceinate ions forming a __________ adsorption product.
reddish pink
28
The _______________ of a substance in the precipitation method is obtained by dividing the molecular weight by the total valence of the precipitating or precipitated ion
gram-equivalent weight
29
Method of titration if FAS is used as an indicator.
Volhard's Method
30
What is the endpoint in Mohr's Method?
Reddish silver chromate
31
Substances assayed: ❖ mainly used for determination of halides (Cl-, Br- & I-), SCN-,CN- and some compounds that form insoluble products (ppt) with AgNO3
32
Volhard Method is (direct/residual)?
Residual
33
Mohr's Method is (direct/residual)?
Direct