Final answer:
The color change of Benedict's solution when heated with a reducing sugar indicates the sugar's concentration: green for the lowest, then yellow, orange, and brick red for the highest levels. This test is particularly useful for diabetes screening.
Step-by-step explanation:
The color change shown by Benedict's solution when heated with a reducing sugar varies depending on the concentration of the sugar. The principle behind this reaction is the reduction of cupric ions (Cu2+) to cuprous ions (Cu2O), leading to the formation of a colored precipitate. Here is the color range associated with the amount of reducing sugar:
- Green precipitate for the low percentage of reducing sugar
- Yellow precipitate as the percentage increases
- Orange precipitate for higher concentration
- Brick red precipitate indicates a high level of reduced sugar
This test is specific for detecting reducing sugars like glucose in urine, which is an important diagnostic tool for conditions such as diabetes mellitus. In the context of diabetes screening, a color change to green indicates 0.5% glucose in the urine, yellow signals 1.0%, orange represents 1.5%, and brick red means greater than 2.0% glucose concentration.
Caution: Appropriate safety measures, like wearing goggles, should be taken while performing the Benedict's test, especially when working with heat or chemicals.