Titration

Question 1

TYPE OF TITRATIONS

Answer 1

1. Acid-base titrations
2. Complexometric titrations
3. Redox titrations
4. Precipitation titrations

Question 2

In which an acidic or basic titrant reacts with an analyte that is a base or an acid.

Answer 2

Acid-base titrations

Question 3

involving a metal-ligand complexation reaction.

Answer 3

Complexometric titrations

Question 4

in which the analyte and titrant react to form a precipitate.

Answer 4

Precipitation titrations

Question 5

where the titrant is an oxidizing or reducing agent.

Answer 5

Redox titrations

Question 6

Based on the formation of a complex between the analyte and the titrant. The chelating agent EDTA is commonly used to titrate metal ions in solution.

Answer 6

Complexometric titrations

Question 7

Based on the formation of a complex between the analyte and the titrant. The chelating agent EDTA is commonly used to titrate metal ions in solution.

Answer 7

Complexometric titrations

Question 8

One of the most common chelating agents used for complexometric titrations in analytical chemistry.

Answer 8

EDTA (Ethylenediaminetetraacetic acid)

Question 9

a well-known complexing agent.

Answer 9

Disodium salt of Ethylene Diamine Tetra Acetic acid

Question 10

are present in hard water.

Answer 10

Calcium (Ca) and Magnesium (Mg) ions

Question 11

When EBT is (Eriochrome Black T) added to hard water EBT forms an

Answer 11

unstable wine-red colour complex with Ca and Mg ions at pH 9-10.

Question 12

When EDTA is added into the hard water, the metal ions form

Answer 12

a stable metal complex with EDTA by leaving the indicator.

Question 13

When all the metal ions are taken by EDTA from the indicator metal ion complex, the wine red colour changes into

Answer 13

steel blue,

Question 14

steel blue, which indicates

Answer 14

the end point.

Question 15

are useful for determining certain analytes

Answer 15

Titrations with precipitating agents

Question 16

Precipitation Titration - Mohr’s method

Answer 16

• Direct titration
• Basis of endpoint: formation of a coloured secondary precipitate
• Indicator: Potassium chromate (K,CrO,)

Question 17

In this method CH ion solution is directly titrated against AgNO, using potassium chromate (K,CrO,) as the indicator.

Answer 17

ESTIMATION OF CHLORIDE (BY MOHR’S METHOD)

Question 18

At the end point, when all the chloride ions are removed. The yellow colour of chromate changes into

Answer 18

reddish brown

Question 19

are based on an oxidation-reduction reaction between the analyte and titrant. Redox titrations are carried out by using a potentiometer or a redox indicator to determine the endpoint.

Answer 19

REDOX TITRATIONS

Question 20

which is used as an indicator.

Answer 20

Blue violet colour of Diphenylamine

Question 21

Molarity (M)

Answer 21

moles/litre or mmoles/mL

Question 22

Normality(N)

Answer 22

equivalence/litre or meq/mL

Question 23

Formality(F)

Answer 23

is identical to molarity

Question 24

Molality(m)

Answer 24

moles/1000g solvent

Question 25

Measuring the volume of a solution of a known concentration (e.g., mol/L) that is needed to react completely with the analyte.

Answer 25

Volumetric titrimetry:

Question 26

Measuring the mass of a solution of a known concentration (e.g., mol/kg) that is needed to react completely with the analyte.

Answer 26

Gravimetric (weight) titrimetry:

Question 27

Measuring total charge (current x time) to complete the redox reaction, then estimating analyte concentration by the moles of electron transferred.

Answer 27

Coulometric titrimetry:

Question 28

A reagent of known concentration.

Answer 28

Standard solution:

Question 29

A titration procedure is carried out
without analyte (e.g., a distilled water sample). It is used to correct titration error.

Answer 29

Blank Titration:

Question 30

A titration in which the amount of analyte is determined by a standard solution directly.

Answer 30

Direct titration:

Question 31

A titration in which a (known amounts) excess reagent is added to a solution to react with the analyte. The excess reagent remaining after its reaction with the analyte, is determined by a titration.

Answer 31

Back titration:

Question 32

An ultrapure compound that serves as the reference material for a titration or for another type of quantitative analysis.

Answer 32

Primary standard:

Question 33

The primary standard ready to be weighted and used to prepare a solution with known concentration

Answer 33

primary standard solution

Question 34

Requirements of primary reagent are

Answer 34

1. Known stoichiometric composition
2. High purity.
3. Atmospheric stable.
4. Absence of hydrate water and nonhygroscopic.
5. Modest cost.
6. Reasonable solubility in the medium.
7. Reasonably large molar mass.

Question 35

The ideal standard solution for a titrimetric method will:

Answer 35

1. be sufficiently stable, therefore, we need to determine its concentration only once;
2. react rapidly with the analyte so that the time required between additions of reagent is minimized;
3. react more or less completely with the analyte so that satisfactory end points are obtained;
4. undergo a selective reaction with the analyte that can be described by a balanced equation.

Question 36

The process by which the concentration of a reagent is determined by titrating it against another standard solution.

Answer 36

Standardization:

Question 37

A standard solution which is standardized against a primary standard.

Answer 37

Secondary standard solution:

Question 38

The conceptual flow chart

Answer 38

1. Primary standard
2. Standardization
3. Secondary standard
4. Titrating sample

Question 39

also called mass or weight titration

Answer 39

GRAVIMETRIC TITRATIONS

Question 40

Advantages of gravimetric titrations

Answer 40

1. Calibration of glassware and tedious cleaning to ensure proper drainage are unnecessary.
2. Temperature corrections for the concentrations are
   unnecessary.
3. Mass measurements are considerably greater precision and accuracy than volume measurements.
4. More easily automated than are volumetric titrations.