Chapter 14: Applications of Neutralization Titrations Flashcards
TRUE or FALSE
Solutions of HCl, HClO4, and H2SO4 are stable indefinitely. Restandardization is not required unless evaporation occurs.
TRUE
widely used as standard solutions for titrating bases
HCl
TRUE or FALSE
solutions of 0.1 M HCl can be boiled for as long as an hour without loss of acid, provided that the water lost by evaporation is periodically replaced
TRUE
TRUE or FALSE
0.5 M solutions can be boiled for at least 10 minutes without significant loss
TRUE
TRUE or FALSE
Standard solutions of nitric acid is seldom used because of its oxidizing properties
TRUE
To obtain most standard acid solutions, a solution of an approximate concentration is first prepared by diluting the concentrated reagent. The diluted acid solution is then standardized against a
primary-standard base
TRUE or FALSE
Primary-standard–grade sodium carbonate is available commercially or can be prepared
by heating purified sodium hydrogen carbonate between 270C and 300C
for 1 hour
TRUE
is the most common base for preparing standard solutions, although potassium hydroxide and barium hydroxide are also used.
sodium hydroxide
The effective concentration of the base is thus diminished by absorption of carbon dioxide, and a systematic error called the
carbonate error
TRUE or FALSE
Carbonate ion in standard base solutions decrease the sharpness of end points and is usually removed before standardization.
TRUE
is a nearly ideal primary standard. It is a nonhygroscopic crystalline solid with a relatively large molar mass (204.2 g/mol)
KHP (potassium hydrogen phthalate)
Several excellent primary standards are available for standardizing bases but most are ___________ that require the use of an indicator with a basic transition range
weak organic acids
what bases are used for standardization of acids
sodium carbonate
TRIS (tris-hydroxymethylaminomethane)
sodium tetraborate decahydrate
mercury (II) oxide
TRUE or FALSE
In solution as well as in the solid state, the hydroxides of sodium, potassium, and barium
react rapidly with atmospheric carbon dioxide to produce the corresponding carbonate
TRUE
TRUE or FALSE
the presence of carbonate ions does not cause a carbonate error provided the same indicator is used for both standardization and analysis, which carbonate does, however, decrease the sharpness of end points and thus is removed before a solution of a base is standardized
TRUE
TRUE or FALSE
best method for preparing carbonate-free sodium hydroxide solutions is to vacuum filter the carbonate given its low solubility
TRUE
TRUE or FALSE
A tightly capped low-density polyethylene bottle usually provides adequate shortterm
protection against the uptake of atmospheric carbon dioxide
TRUE
is an excellent primary standard with a
high molar mass per mole of protons. It is also a strong acid that can be titrated using
virtually any indicator with a transition range between pH 4 and 10.
potassium hydrogen iodate
what acids are used in standardizing bases
potassium hydrogen phthalate
benzoic acids
potassium hydrogen iodate
are used to determine the many inorganic, organic, and biological species that possess acidic or basic properties
neutralization titrations
2 major types of end points
visual end point
potentiometric end point
the potential of a glass/calomel electrode system is determined with a pH meter or another voltage measuring device
potentiometric endpoint
what elements that occur in organic and biological systems are conveniently determined by methods that have an acid-base titration as the final step
nonmetal elements
carbon
nitrogen
chlorine
bromine
fluorine
occurs in a wide variety of substances of interest in the life sciences, in industry, and in agriculture. Examples include amino acids, proteins, synthetic drugs, fertilizers, explosives, soils, potable water supplies, and dyes
nitrogen
most common method for determining organic nitrogen is the. sample is decomposed in hot conc sulfuric acid to convert the bound nitrogen to ammonium ion, which is then cooled, diluted, and made basic
Kjeldahl method