Official Assays

TITRIMETRY involves a:

solution of reagent of known concentration (known as _______)
added to a
solution of unknown concentration (known as ________)
until reaction is considered complete (known as __________)

titrant
analyte
endpoint

refers to standard solution used with known concentration

titrant

refers to active constituent to be analyzed; unknown concentration

analyte / titrand / sample

refers to chemicals capable of changing colors when end point or near the endpoint is reached

indicators

is the point of which reaction is observed to be complete (visible)

end point

is the point at which a chemically equivalent amount of titrant has reacted with analyte

equivalence point

equivalence point is aka ______________

stoichiometric point

equivalence point is reached (BEFORE / AFTER) end point

before

expression of equivalency of titrant and analyte; mg analye/ ml titrant

titer value

refers to gram of substance that is chemically equivalent to ml of volumetric solution

titer value

titration error is calculated as: __________________

titration error = equivalence point - end point

is the process of determining the exact concentration of a volumetric solution using a known amount of primary or secondary solution

standardization

a volumetric solution that is almost 100% pure; does not require standardization

primary standard VS

a volumetric solution that needs standardization against primary standard or previously standardized volumetric solutions

secondary standard VS

are compounds of high purity used for the standardization of volumetric solutions used in titrations

primary standard

give the primary standard for the secondary standard vs:

NaOH VS (sodium hydroxide) = ____________

KHP (potassium hydrogen phthalate)

give the primary standard for the secondary standard vs:

Na2S2O3 VS (sodium thiosulfate) = ____________

KIO3 (potassium iodate)

give the primary standard for the secondary standard vs:

HCl VS (Hydrochloric acid) = ____________

Anhydrous Na2CO3 (anhydrous sodium carbonate)

give the primary standard for the secondary standard vs:

EDTA VS (ethylenediaminetetraacetate)= ____________

Zn metal (Zinc metal)

type of titration that makes use of indicators

visual titration

type of titration in which equivalence point is indicated by sharp change in the potential of the solution

potentiometric titration

type of titration in which equivalence point is indicated by a change in electrical conductivity

electrometric titration

type of titration in which analyte is reacted with titrant after rendering it soluble in the titration medium

direct titration

type of titration in which analyte undergoes preliminary treatment before titration (2 VS)

indirect titration

type of titration in which a measured excess of one VS is added; unreacted excess then backtitrated with another VS

residual titration

is a process under titrimetry in which assay shall be conducted using same quantities of same reagents treated in same manner as the solution or mixture contain the portion of the assay of the substance under assay or test, but WITHOUT the substance to be analyzed

blank determination

name all chemical reaction in titrimetry

neutralization
reduction-oxidation
precipitation
complexation

a chemical reaction under titrimetry that invoves acid-base reactions

neutralization

give indicators used in aqueous medium of (SA + SB):
________________________

phenolphthalein
methyl orange
methyl red

give indicators used in aqueous medium of (WA + SB):
________________________

phenolphthalein

give indicators used in aqueous medium of (SA + WB):
________________________

methyl red

give indicators used in nonaqueous medium of (SA):
________________________

thymol blue

give indicators used in nonaqueous medium of (WA):
________________________

azoviolet
o-nitroaniline

give indicators used in nonaqueous medium of (Relatively SB):
________________________

methyl red
methyl orange

give indicators used in nonaqueous medium of (WB + salt):
________________________

crystal violet
malachite green

in acidimetry:

Titrant: (ACID / BASE)
Analyte: (ACID / BASE)

acid
base

in alkalimetry:

Titrant: (ACID / BASE)
Analyte: (ACID / BASE)

base
acid

give the respective colors of the following indicators (phthaleins) in ACID:

phenolphthalein: ________
thymolphthalein: ________

colorless
colorless

give the respective colors of the following indicators (phthaleins) in BASE:

phenolphthalein: ________
thymolphthalein: ________

pink
blue

give the respective colors of the following indicators (sulfonphthaleins) in ACID:

thymol blue: ___________
bromophenol blue: ________
bromothymol blue: ________
bromocresol green: ________
bromocresol purple: ________
phenol red: _________
cresol red: _________
malachite green: __________

yellow

give the respective colors of the following indicators (sulfonphthaleins) in BASE:

thymol blue: ___________
bromophenol blue: ________
bromothymol blue: ________
bromocresol green: ________
bromocresol purple: ________
phenol red: _________
cresol red: _________
malachite green: __________

blue
blue
blue
blue
purple
red
red
green

give the respective colors of the following indicators (azo dyes) in ACID:

methyl red: _________
methyl yellow: _________
methyl orange: _________

red
red
pink

give the respective colors of the following indicators (azo dyes) in BASE:

methyl red: _________
methyl yellow: _________
methyl orange: _________

yellow

a chemical reaction that pertains to analysis involving a change in valence of the reacting substances

Redox reactions (reduction-oxidation)

in redox reactions, the ___________ is the reactant in which loses electrons

reducing agent

in redox reactions, the ___________ is the reactant in which gains electrons

oxidizing agent

in redox reactions, the ___________ is the reactant that is oxidized

reducing agent

in redox reactions, the ___________ is the reactant that is reduced

oxidizing agent

name the different redox titrations:

permanganometry
cerimetry
iodimetry
iodometry

give the ff for PERMANGANOMETRY:

titrant:
primary std:
indicator + color:

KMnO4 VS (potassium permanganate)
Na₂C₂O₄ (sodium oxalate)
none (pink)

give examples under PERMANGANOMETRY for the ff:

direct:
indirect:
residual:

H2O2 topical solution
malic acid in cherry juice
KNO2 (potassium nitrite)

give the ff for CERIMETRY:

titrant:
primary std:
indicator + color :

Ce(SO4)2 (cerium sulfate)
Na2C2O4 (sodium oxalate)
o-phenanthroline (red to blue)

give examples under CERIMETRY for the ff:

direct:

FeSO4 tablets, Menadione

Iodimetry is used for assay of (REDUCING / OXIDIZING) agents

reducing

Iodometry is used for assay of (REDUCING / OXIDIZING) agents

oxidizing

give the ff for IODIMETRY:

titrant:
primary std:
indicator + color :

Iodine
As2O3 (arsenic trioxide)
starch (blue)

give examples under IODIMETRY for the ff:

direct:
residual:

ascorbic acid
calomel

give the ff for IODOMETRY:

titrant:
primary std:
indicator + color :

Na2S2O3 (sodium thiosulfate)
K2Cr2O7 (potassium chromate)
starch (disappearance of blue)

give examples under IODOMETRY for the ff:

direct:
residual:

CuSO4
phenol

name the three methods under precipitation titration

volhard
mohr
fajans

the method under precipitation titration that is residual

volhard

what is the back titrant for volhard?

NH4SCN (ammonium thiocyanate)

name the titrant used for precipitation titrations: _______

AgNO3

give the indicator and endpoint for Volhard titration

Ferric ammonium sulfate
bloody red

give the indicator and endpoint for Mohr titration

potassium chromate
red ppt

give the indicator and endpoint for Fajans titration

Eosin Y or DCF
pink ppt

a chemical reaction in titrimetry that is a method of choice for the determination of metal ions, except group 1 metals

complexometry

a compound formed when a metal ion combines with a molecule which can donate electrons

complex

___________ when the combining molecule has 2 or more groups which can donate electrons

chelate

______________ is widely used complexing agent

Ethylenediaminetetraacetic Acid