2nd Exam - TITRATION METHOD

Question 1

based upon measuring the amount of reagent of known concentration that is consumed by the analyte

are capable of rapid and convenient analyte determinations with high accuracy and precision

Answer 1

Titrimetric Methods of Analysis

Question 2

involves measuring the volume of a
solution of known concentration that is needed to react
essentially and completely with the analyte

Answer 2

Volumetric Titrimetry

Question 3

differs only in that the mass of the
reagent is measured instead of its volume

Answer 3

Gravimetric Titrimetry

Question 4

the reagent is a constant direct
electric current of known magnitude that is directly or
indirectly reacts with the analyte here, the time required to
complete the electrochemical reaction is measured

Answer 4

Coulometric Titrimetry

Question 5

most common reaction types in titrations

Answer 5

acid-base, redox, precipitation and complex reactions.

Question 6

T or F? The concentration of the titrant solution, CT, must be known accurately

Answer 6

T

Question 7

The ______ solution must be standardized either by preparing it using a primary standard or, more commonly, titrating it against a solution prepared with a primary standard

Answer 7

titrant

Question 8

is a reagent of exactly known
concentration that is used in a titrimetric analysis

Answer 8

standard solution

Question 9

is an ultrapure compound that serves as the reference material for a titrimetric method of analysis

Answer 9

primary standard

Question 10

Titration solution requirements

Answer 10

• high purity
• stability towards air
• absence of water of hydration
• ready availability at modest cost
• reasonable solubility in the titration medium
• reasonably large molar mass so that the relative error associated with weighing the standard is minimized

Question 11

is a compound whose purity has been
established by chemical analysis and that serves as the
reference material for a titrimetric method of analysis

Answer 11

secondary standard

Question 12

is a process in which a standard reagent is added
to a solution of an analyte until the reaction between the analyte and the reagent is judged to be complete

Answer 12

titration

Question 13

is a process in which the excess of a standard
solution used to consume an analyte is determined by titration with a second standard solution

are often required when the rate of reaction between the analyte and reagent is slow or when the standard solution lacks stability

Answer 13

back-titration

Question 14

is a process in which the concentration of a
volumetric solution (secondary standard) is determined by using it to titrate a known mass of a primary standard or an exactly known volume of another secondary standard solution

Answer 14

standardization

Question 15

is the point in a titration when the amount of
added standard reagent is exactly equivalent to the amount of analyte

Answer 15

equivalence point

Question 16

is the point in a titration when a physical change
occurs that is associated with the condition of chemical equivalence

Answer 16

end point

Question 17

The difference in volume or mass between the equivalence point and the end point is the

Answer 17

titration error

Et= Vep-Veq

Question 18

are added to the analyte solution to
produce an observable physical change the end
point at or near the equivalence point change
in color or appearance or disappearance of
turbidity

Answer 18

indicators

Question 19

here, a carefully weighed quantity
of a primary standard is dissolved in a suitable
solvent and diluted to an exactly known volume in a
volumetric flask

Answer 19

direct method

Question 20

In standardization, the ______ to be
standardized is used to titrate:
- a weighed quantity of primary standard,
- a weighed quantity of secondary standard,
- a measured volume of another standard solution

Answer 20

titrant

Question 21

is based on the neutralization
reaction between the analyte and an acidic or basic
titrant These most commonly use a pH indicator, a pH
meter, or a conductance meter to determine the
endpoint

Answer 21

acid-base titration

Question 22

is based on an oxidation reduction
reaction between the analyte and titrant These most
commonly use a potentiometer or a redox indicator to
determine the endpoint Frequently either the reactants
or the titrant have a color intense enough that an
additional indicator is not needed

Answer 22

redox titration

Question 23

is based on the formation of a
complex between the analyte and the titrant

Answer 23

Complexometric titration

Question 24

is very commonly used to titrate metal ions in
solution Requires specialized indicators that form weaker complexes with the metal A

Answer 24

chelating agent EDTA

Question 25

common example of EDTA (for the titration of calcium and magnesium ions)

Answer 25

Eriochrome Black T

Question 26

The titrant forms an insoluble product with the analyte Example is the titration of chloride ion with silver nitrate solution to form silver chloride precipitate Indicators can be used to detect the end point or potential of the solution can be monitored electrically

Answer 26

Precipitation titration

Question 27

small amount of sample used for analysis

Answer 27

aliquot

Question 28

of a solution is the mass (in mg) of a substance that is chemically equivalent to 1 mL of the solution.

Answer 28

titer

Question 29

To analyze a sample of unknown purity the analyst weighs accurately a portion of the sample, dissolves it appropriately, and titrates it with a standard solution.

Answer 29

percent purity

Question 30

for nitrogen determination

Answer 30

Kjeldahl method