COMPLEXATION AND PRECIPITATION REACTIONS IN TITRATION

Question 1

are widely used in analytical chemistry.
One of the earliest uses of these reactions was for titrating cations.

Answer 1

Complexation reactions

Question 2

is an ion or a molecule that forms a covalent bond with a cation or a neutral metal atom by donating a pair of electrons, which are then shared by the two.

Answer 2

LIGAND

Question 3

common inorganic ligands

Answer 3

Water, Ammonia, and Halide Ions

Question 4

The number of covalent bonds that a cation tends to form with electron donors is its ___

Answer 4

coordination number.

Question 4

The number of covalent bonds that a cation tends to form with electron donors is its ___

Answer 4

coordination number.

Question 5

Titrations based on complex formation, sometimes called ____ , have been used for more than a century.

Answer 5

complexometric titrations

Question 6

Remarkable growth in their analytical application, based on a particular class of coordination compounds called

Answer 6

chelates

Question 7

A ligand that has a single donor group, such as ammonia, is called

Answer 7

unidentate

Question 8

has two groups available for covalent bonding, is called

Answer 8

bidentate

Question 9

molecules containing nine or more atoms in the cycle and include at least three heteroatoms, usually oxygen, nitrogen or sulfur.

Answer 9

MACROCYCLES

Question 10

Earliest complexation reaction used in analytical chemistry

Answer 10

Complexometric Titration -

Question 11

is one of the oldest analytical techniques, dating back to the mid-1800s
It is based on reactions that yield ionic compounds of limited solubility

Answer 11

Precipitation Titration

Question 12

Titrations with silver nitrate are sometimes called

Answer 12

argentometric titrations

Question 13

is one of the most common argentometric methods. In this method, silver ions are titrated with a standard solution of thiocyanate ion.

Answer 13

The Volhard method

Question 14

sodium chromate serves as the indicator for the argentometric titration of chloride, bromide, and cyanide ions -

Answer 14

Mohr Method

Question 15

uses an adsorption indicator

Answer 15

Fajans Method

Question 16

first described by K. Fajans, a Polish chemist in 1926
Is an organic compound that adsorbs onto or desorbs from the surface of the solid in a precipitation titration

Answer 16

Adsorption Indicator

Question 17

is the most widely used complexometric titrant
it has six potential sites for bonding a metal ion: the four carboxyl groups and the two amino groups, each of the latter with an unshared pair of electrons

Answer 17

Ethylenediaminetetraacetic Acid (EDTA)

Question 18

is a typical metal-ion indicator that is used in the titration of several common cations

Answer 18

Eriochrome Black T

Question 19

If direct indicator for the analyte is unavailable, a small amount of a metal ion for which a good indicator is available can be added. The metal ion must form a complex that is less stable than the analyte complex.

Answer 19

Methods Based on Indicators for an Added Metal Ion

Question 20

Potential measurements can be used for end-point detection in the EDTA titration of those metal ions for which specific ion electrodes are available.

Answer 20

Potentiometric Methods

Question 21

Measurement of UV/visible absorption can also be used to determine the end points of titrations. In these cases, a spectrophotometer responds to the color change in the titration rather than relying on a visual determination of the end point

Answer 21

Spectrophotometric Methods

Question 22

are useful for the determination of cations that form stable EDTA complexes and for which a satisfactory indicator is not available.

Answer 22

Back-titrations

Question 23

an unmeasured excess of a solution containing the magnesium or zinc complex of EDTA is introduced into the analyte solution. If the analyte forms a more stable complex than that of magnesium or zinc

Answer 23

displacement titrations

Question 24

is a complexing agent that reacts selectively with a component in a solution to prevent that component from interfering in a determination

Answer 24

MASKING AGENT

Question 25

is often used as a masking agent to permit the titration of magnesium and calcium ions in the presence of ions such as cadmium, cobalt, copper, nickel, zinc, and palladium.

Answer 25

Cyanide ion

Question 26

which forms the least stable EDTA complex of all of the common multivalent cations in typical water samples, is not titrated until enough reagent has been added to complex all of the other cations in the sample.

Answer 26

Magnesium