Question detail

For Purity, formulations and chromatography, which option uses the correct Chemical analysis evidence for pure substance?

Try the question, check the answer, then read the explanation to understand the curriculum point.

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At a glance

MCQ

Type

practice

Style

Topic

Purity, formulations and chromatography

Question

A. It raises the boiling point
B. It lowers the boiling point
C. It has no effect on the boiling point
D. It makes the boiling point unpredictable

Answer

The correct answer is It lowers the boiling 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 It lowers the boiling point. This response is stronger than the distractors because it keeps the test, observation, and interpretation in the correct order for pure substance. Other options are weaker when they confuse gas tests, flame colours, ion-test precipitates, chromatography evidence, or pure-substance/formulation wording.

Common mistake

Misunderstanding Pure Substances

Students often confuse the scientific definition of a pure substance with everyday uses of the term, thinking that any clean-looking substance is pure.

Emphasize that in chemistry, a pure substance is a single element or compound, not mixed with any other substance, regardless of its appearance.

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