Qualitative Analysis of Ions - Applications
Q. In qualitative analysis, what does the presence of a white precipitate indicate when testing for chloride ions?
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A.
Presence of sulfate ions
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B.
Presence of phosphate ions
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C.
Presence of chloride ions
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D.
Presence of nitrate ions
Solution
A white precipitate formed when adding silver nitrate to a solution indicates the presence of chloride ions.
Correct Answer: C — Presence of chloride ions
Q. In qualitative analysis, what does the term 'chromatographic retention time' refer to?
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A.
The time taken for a sample to reach the detector
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B.
The time taken for a solvent to evaporate
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C.
The time taken for a compound to elute from the column
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D.
The time taken for a reaction to complete
Solution
Chromatographic retention time refers to the time taken for a compound to elute from the column, which helps in identifying the compound.
Correct Answer: C — The time taken for a compound to elute from the column
Q. What does a positive test for sulfate ions typically produce when barium chloride is added?
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A.
A blue solution
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B.
A white precipitate
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C.
A yellow solution
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D.
No change
Solution
A positive test for sulfate ions produces a white precipitate of barium sulfate when barium chloride is added.
Correct Answer: B — A white precipitate
Q. What is the primary purpose of using flame tests in qualitative analysis of ions?
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A.
To determine the concentration of ions
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B.
To identify the presence of specific metal ions
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C.
To separate ions in a mixture
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D.
To measure the pH of a solution
Solution
Flame tests are used to identify the presence of specific metal ions based on the characteristic colors they emit when heated in a flame.
Correct Answer: B — To identify the presence of specific metal ions
Q. What is the role of indicators in titration for qualitative analysis?
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A.
To increase the reaction rate
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B.
To provide a color change at the endpoint
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C.
To stabilize the solution
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D.
To separate the ions
Solution
Indicators are used in titrations to provide a visual color change at the endpoint, helping to identify the completion of the reaction.
Correct Answer: B — To provide a color change at the endpoint
Q. What is the significance of using UV-Vis spectroscopy in qualitative analysis?
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A.
To measure the mass of ions
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B.
To identify the presence of colored ions
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C.
To separate ions based on size
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D.
To determine the boiling point of a solution
Solution
UV-Vis spectroscopy is significant in qualitative analysis as it can identify the presence of colored ions based on their absorbance characteristics.
Correct Answer: B — To identify the presence of colored ions
Q. Which of the following methods is best suited for the qualitative analysis of cations in a mixture?
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A.
Spectrophotometry
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B.
Ion chromatography
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C.
Precipitation reactions
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D.
Mass spectrometry
Solution
Precipitation reactions are commonly used to qualitatively analyze cations by forming insoluble compounds that can be visually identified.
Correct Answer: C — Precipitation reactions
Q. Which qualitative analysis technique can separate amino acids based on their charge?
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A.
Thin-layer chromatography
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B.
Gel electrophoresis
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C.
Gas chromatography
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D.
Liquid-liquid extraction
Solution
Gel electrophoresis separates amino acids based on their charge and size, making it effective for qualitative analysis.
Correct Answer: B — Gel electrophoresis
Q. Which technique is commonly used to separate anions in qualitative analysis?
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A.
Gas chromatography
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B.
Thin-layer chromatography
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C.
Capillary electrophoresis
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D.
High-performance liquid chromatography
Solution
Capillary electrophoresis is effective for separating anions based on their charge and size, making it suitable for qualitative analysis.
Correct Answer: C — Capillary electrophoresis
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