Question

question 6
what color did the water turn when the biuret reagent was added?
blue
yellow
red
purple

question 7
what color did the milk turn when the biuret reagent was added?
blue
yellow
red
purple

question 8
what color did the glucose solution turn when the biuret reagent was added?
blue
yellow
red
purple

Explanation:

The biuret reagent is used to detect proteins. Water has no proteins, so it remains the blue - color of the biuret reagent itself. Milk contains proteins, and when biuret reagent is added to milk, it turns purple due to the reaction with proteins. Glucose solution has no proteins, so it also remains the blue - color of the biuret reagent.

Answer:

Question 6: A. blue
Question 7: D. purple
Question 8: A. blue