Question detail
Which statement would earn credit for Explain that impurities change the melting point and boiling point of a substance.?
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. They raise the melting point.
- B. They lower the melting point.
- C. They do not affect the melting point.
- D. They cause the melting point to vary unpredictably.
Answer
The correct answer is They lower the melting point.. It matches pure substance because the evidence is single element or compound / fixed melting point and the expected result is purity evidence.
Explanation
The correct option is They lower the melting point.. The answer stays inside Purity, formulations and chromatography by linking the observation to the conclusion instead of naming a substance without evidence. Other options are weaker when they confuse gas tests, flame colours, ion-test precipitates, chromatography evidence, or pure-substance/formulation wording.
Common mistake
Impurities and Melting/Boiling Points
Students often think that impurities only affect the boiling point of a substance, ignoring their impact on the melting point.
Remember that impurities can change both the melting point and boiling point of a substance, causing them to be lower than those of the pure substance.
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