Question detail
For Purity, formulations and chromatography, which option uses the correct Chemical analysis evidence for chromatography?
Try the question, check the answer, then read the explanation to understand the curriculum point.
At a glance
MCQ
Type
practice
Style
Topic
Purity, formulations and chromatography
Question
- A. Multiple spots
- B. No spots
- C. A single spot
- D. A blurred line
Answer
The correct answer is A single spot. It matches chromatography because the evidence is spot and solvent-front distances and the expected result is Rf or separation evidence.
Explanation
The correct option is A single spot. This response is stronger than the distractors because it keeps the test, observation, and interpretation in the correct order for chromatography. Other options are weaker when they confuse gas tests, flame colours, ion-test precipitates, chromatography evidence, or pure-substance/formulation wording.
Common mistake
Misunderstanding Rf Values
Students often confuse Rf values with absolute measurements, thinking they represent the actual distance a substance travels rather than a ratio.
Emphasize that Rf values are calculated as the distance moved by the substance divided by the distance moved by the solvent, and they are dimensionless ratios used for comparison.
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