Question

lynn performed the benedict test on water (tube a) and three samples of variable simple sugar concentration (tubes b, c, d). which of the following best explains the experimental results observed in tube a?

tube a was contaminated by the contents of one of the other tubes.

benedict reagent was not added to tube a.

Explanation:

Analyze the expected result for Tube A

Water contains no reducing sugars, so Benedict's test on water (Tube A) should yield a negative result (remaining blue).

Identify the observed result in Tube A

The image shows Tube A has turned a reddish-brown/orange color, which indicates a positive test result for reducing sugars.

Determine the most likely explanation

Since water should not contain reducing sugars, the unexpected positive result in Tube A is best explained by contamination from one of the other tubes containing simple sugars.

Answer:

• Tube A was contaminated by the contents of one of the other tubes. (Correct answer)
• Benedict reagent was not added to Tube A.