本题目来源于试卷: Models of Matter A.1 Introduction to the Particulate Nature of Matter，类别为 IB化学
[单选题]
A dye has been contaminated with another substance, and this dye undergoes recrystallization in an attempt to remove the contaminant.
Which of the paper chromatograms below (A, B, C, or D) indicates that the recrystallization successfully removed the contaminant? Each chromatogram contains a before recrystallization (1) and after recrystallization (2).
A.
B.
C.
D.
参考答案: A
本题详细解析:
The student must first understand that each component of the mixture will result in one spot on the paper chromatogram. If the recrystallization was successful, then the purified dye should only have one dot.
Therefore, answer choice B is incorrect since the sample contains more than one component after recrystallization.
Answer choice C indicates that the dye is no longer in the sample, and answer choice D indicates the contaminant was not successfully separated from the dye. So the paper chromatogram is unable to identify any impurities that are still present.
In answer choice A, before recrystallization, shows two components (the dye and contaminant), and after, there is only one component showing successful recrystallization.
This question is categorized as medium since the student must understand the premise and purpose of paper chromatography and apply it to experimental results.
| 
