Ch 16 Applications of Neutralization Titrations Flashcards
are widely used to determine the concentration of acidic or basic
analytes or analytes that can be converted to acids or bases by suitable treatment.
Neutralization titrations
is the usual solvent for neutralization titrations because it is convenient, inexpensive,
and nontoxic.
Water
is the most frequently used reagent for standardizing acids. Several
other reagents are also used.
Sodium carbonate
is the most common base for preparing standard solutions,
although potassium hydroxide and barium hydroxide are also used
Sodium hydroxide
Name primary standards are available for standardizing bases
Potassium Hydrogen Phthalate
Benzoic acid
Potassium hydrogen iodate
The most common method for determining organic nitrogen is the __________, which is based on a neutralization titration
Kjeldahl
method
a reagent containing copper(II) ions is used, and a violet colored complex is formed
between the Cu21 ions and peptide bonds. The increase in the absorption of visible
radiation is used to measure serum protein
biuret method,
the serum sample is pretreated with an alkaline copper solution
followed by a phenolic reagent
Lowry method
the sample is mixed with powdered copper(II) oxide and ignited in a combustion tube to give carbon dioxide, water, nitrogen, and small amounts
of nitrogen oxides. A
Dumas method,
Name methods for the determination of organic nitrogen
Kjeldahl
Biuret
Lowry
Dumas
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
In th3 determination of _____, organic and biological materials is conveniently determined by burning
the sample in a stream of oxygen.
Sulfur
Various inorganic species namely,______, can be determined by titration with strong acids or bases
Ammonium salts
Nitrates and nitrites
Carbonate
Species transformation in Kjeldahl
Nitrogen species from the sample > ammonium ions > ammonia
Trace the determination of sulfur using titration method
Sulfur in sample is determined by burning
the sample in a stream of oxygen. The sulfur dioxide (as well as the sulfur trioxide)
formed is collected via distillation with diluted hydrogen peroxide. The sulfuric acid is then titrated with standard base
Trace the determination of ammonium salts using titration method
conversion to ammonia with
strong base followed by distillation. The ammonia is collected and titrated as in the
Kjeldahl method
Trace the determination of nitrate and nitrite using titration method
The nitrate and nitrite ions in a sample are first reduced to ammonium ion by
reaction with an alloy of 50% Cu, 45% Al, and 5% Zn(Devarda’s alloy). Traces of the alloy are introduced into a strongly alkaline solution of the sample and the ammonia is distilled after reaction is complete, then titrated
How are carbonates and hydroxide determine?
Winkler method
Elucidate wrinkler method
The carbonate/hydroxide mixtures are titrated with standard acid to the endpoint with an acid-range indicator. Carbonate ion is then precipitated from the mixture by adding barium chloride, following which the hydroxide
ion is titrated to a phenolphthalein end point.
Organic Functional Groups that can be determine using the neutralization titration
Carboxylic and Sulfonic Acid Groups
Amine
Ester
Hydroxyl
Carbonyl
Trace the determination of carboxylic group using titration method
the acid is not soluble in water so it needs to be dissolved in ethanol and titrated with aqueous base OR
the acid can be dissolved in an
excess of standard base followed by back-titration with standard acid.
Trace the determination of sulfonic group using titration method
Sulfonic acids are generally strong acids that easily dissolve in water. Direct titration
with standard base can be used for the determination
The ______________of a participant
in a neutralization reaction is the mass that reacts with or supplies one mole of protons in a particular reaction.
equivalent mass
Trace the determination of amine group using titration method
Aliphatic amines generally have base dissociation constants on the order of 10^-5 and can be titrated directly with a solution of strong acid.
Trace the determination of ester group using titration method
Via saponification.
Typically, the ester is refluxed with
standard 0.5 M KOH for 1 to 2 hours. After cooling, the excess base is titrated with
standard acid.
is the process by which
an ester is hydrolyzed in alkaline solution to give an alcohol and a conjugate
base.
Saponification
Trace the determination of hydroxyl group using titration method
Hydroxyl groups in organic compounds can be determined by esterification
with various carboxylic acid anhydrides or chlorides.
Trace the determination of carbonyl group using titration method
Many aldehydes and ketones can be determined with a solution of hydroxylamine
hydrochloride.. The liberated HCl is titrated with base.
Elucidate The Determination of Salts using titration
The salt is converted to an equivalent amount of an acid or base by passing a
solution containing the salt through a column packed with an ion-exchange resin.
