Question

question 5
a scientist used biuret reagent to test 2 clear liquid substances. the picture above shows the results after the biuret test has been completed.
the test tube on the left (blue) shows a __ result and the test tube on the right (purple) shows a __ result.

• positive ; negative
• positive ; positive
• negative ; positive
• negative ; negative

Explanation:

The Biuret test is used to detect proteins. A negative result (no protein) shows a blue color (like the left - hand tube), while a positive result (protein present) shows a purple color (like the right - hand tube).

Answer:

C. negative ; positive