Question

michael has tested 4 different solutions of variable glucose concentration with benedict reagent. what are the possible explanations for the result observed in tube c?
a b c d
image of four test tubes
select all that apply
a. tube c was contaminated by the contents of one of the other tubes
b. benedict reagent was not added to tube c.
c. tube c was not heated for the correct amount of time
d. the solution added to tube c did not contain simple sugar
which tube has the highest simple sugar concentration?
a. tube a

Explanation:

Part 1: Possible Explanations for Tube C's Result (Select all that apply)

• Option A: Contamination from other tubes could alter Tube C's result, so this is a valid explanation.
• Option B: If Benedict reagent (which is blue initially) wasn't added, Tube C might remain blue (matching its color), so this applies.
• Option C: Incorrect heating time can prevent the color change (e.g., no reduction reaction), keeping it blue, so this is valid.
• Option D: If the solution has no simple sugar, Benedict's test (which detects reducing sugars like glucose) would show the reagent's original blue color, matching Tube C, so this applies.

Benedict's test color intensity (from blue to green/yellow/orange/red) increases with sugar concentration. Tube B is red (or a deep color), indicating the highest sugar concentration (as red is the most intense positive result, showing more sugar reduced the reagent).

Answer:

A. Tube C was contaminated by the contents of one of the other tubes
B. Benedict reagent was not added to Tube C.
C. Tube C was not heated for the correct amount of time
D. The solution added to Tube C did not contain simple sugar

Part 2: Which tube has the highest simple sugar concentration?