Analytical Chemistry Flashcards
Platinum crucibles can be used for the following processes without significant loss except
A. Fusion with sodium carbonate, borax, or alkali bifluorides
B. Evaporation with hydrofluoric acid
C. Ignition of oxides of Ca and Sr
D. Heating with sulfides
D. Heating with sulfides
What is the best basis for choosing the right indicator for a given acid-base titration from among the following?
A. Type of acid
B. Type of base
C. pH at equivalence point
D. Molarity of the acid or base
C. pH at equivalence point
Which of the following does not describe the correct way to wash precipitate?
A. Minimum volume of washing liquid must be used to wash the precipitate
B. Wash with small portions of washing liquid
C. Ionic salts containing common ion must be added to the washing liquid to increase the solubility of the precipitate
D. Gelatinous precipitates require more washing than crystalline precipitate
C. Ionic salts containing common ion must be added to the washing liquid to increase the solubility of the precipitate
It is expressed as the volume of a solution chemically equivalent to a mass of a solid reagent.
A. Titer
B. Aliquot
C. Molarity
D. ppm
A. Titer
Chemicals which are tested by the manufacturers showing the actual percentages of impurities and labeled on the containers are called
A. Reagent grade chemicals
B. Analytical reagent
C. Certified reagent
D. All of these
D. All of these
Process of determining the nitrogen content of organic minerals by mixing the sample with powder copper (II) oxide and ignited to a combustion tube giving CO2, H2O, N2, and small amounts of nitrogen oxides
A. Kjeldahl method
B. Dumas method
C. Winkler method
D. Wij’s method
B. Dumas method
Which of the following is not a correct analytical method-titrant pair?
A. Mohr–AgNO3
B. Fajans–AgNO3
C. Volhard–AgNO3
D. Liebig–AgNO3
C. Volhard–AgNO3
In the analysis of nitrogen using Kjeldahl method, which of the following is added to decompose organic matrices present in the sample?
A. H2SO4
B. HgO
C. K2SO4
D. H2O2
D. H2O2
In Volhard method, why is it necessary to carry out titration in acidic solution?
A. To prevent precipitation of iron as hydrated oxide
B. To prevent formation of AgSCN
C. To prevent reduction of halide
D. To prevent precipitation of silver as hydrated oxide
A. To prevent precipitation of iron as hydrated oxide
Which of the following is not used as primary standard for the standardization of alkali solutions?
A. HgO
B. H2C2O4
C. HSO3NH2
D. C6H5COOH
A. HgO
Which of the following is false about iodine as an oxidizing agent in titration?
A. Standard iodine solutions have low smaller electrode potential
B. Sensitive and reversible indicators are readily available
C. Iodine is very soluble in water and losses are minimal
D. The solution lacks stability and requires regular standardization
C. Iodine is very soluble in water and losses are minimal
Which of the following ions is best titrated with EDTA at minimum pH less than 7?
A. Ca2+
B. Sr2+
C. Mg2+
D. Fe3+
D. Fe3+
Process by which an agglomerated colloid return to uts dispersed state during washing due to leaching of electrolyte responsible for its coagulation.
A. Nucleation
B. Coagulation
C. Agglomeration
D. Peptization
D. Peptization
At pH = 7 and a pressure of 1 bar, the potential for the half-reaction, 2H+ (aq) + 2e- → H2 (g) is
A. 0 V
B. -0.414 V
C. -0.828 V
D. -1.255 V
B. -0.414 V
