A Mystery Investigation Quick Check

Question

4 of 44 of 4 Items
Question
A student is performing a Benedict’s test on an unknown substance. The student adds the reagent (the chemical required to make a color change), and nothing happens. Which conclusion can the student make?(1 point)
Responses

The test was inconclusive because the student needed to also test with iodine or vinegar.
The test was inconclusive because the student needed to also test with iodine or vinegar.

The test was inconclusive because the student forgot to add heat.
The test was inconclusive because the student forgot to add heat.

The substance is not glucose based.
The substance is not glucose based.

The substance is glucose based.
The substance is glucose based.
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Answer 1

In the context of a Benedict's test, which is used to detect reducing sugars (like glucose), the correct conclusion based on the observation that there was no color change after adding the reagent is:

The substance is not glucose based.

When Benedict's reagent is mixed with a reducing sugar and heated, it typically changes color (from blue to green, yellow, orange, or brick red) depending on the amount of sugar present. If no color change occurs, it indicates that the substance is likely not a reducing sugar like glucose.

Note: While it’s also possible that the student could have forgotten to heat the mixture, the question specifically asks for a conclusion from the lack of observable results. Thus, the most straightforward conclusion is about the substance itself.