Question

which solution is the positive control?

starch solution
distilled water
glucose solution

Explanation:

Identify the assay context

The options (Starch, Distilled water, Glucose) and the student's profile indicate this question is in the context of Benedict's test for reducing sugars.

Define positive control

A positive control is a treatment that is known to produce a positive result in the specific experimental assay.

Evaluate the options

• Distilled water contains no sugars and serves as a negative control.
• Starch is a non-reducing polysaccharide and does not react positively with Benedict's reagent.
• Glucose is a reducing monosaccharide that reacts with Benedict's reagent to produce a color change, serving as the positive control.

Answer:

• Starch solution
• Distilled water
• Glucose solution (Correct answer)