NEET BIOLOGY

Detailed explanation-1: -In lab, we used Benedict’s reagent to test for one particular reducing sugar : glucose. Benedict’s reagent starts out aqua-blue. As it is heated in the presence of reducing sugars, it turns yellow to orange. The “hotter” the final color of the reagent, the higher the concentration of reducing sugar.

Detailed explanation-2: -Benedict’s solution is blue but, if simple carbohydrates are present, it will change colour – green/yellow if the amount is low and red if it is high. A precipitate will also form if the sugars are present and the quantity of this gives an indication as to the quantity of sugars in the test sample.

Detailed explanation-3: -A positive test with Benedict’s reagent is shown by a color change from clear blue to brick-red with a precipitate. Generally, Benedict’s test detects the presence of aldehydes, alpha-hydroxy-ketones, and hemiacetals, including those that occur in certain ketoses.

Detailed explanation-4: -It can be noted that Benedict’s test can also be used to check for the presence of glucose in a urine sample. Since this test detects any aldehydes and -hydroxy ketones and glucose is an aldose whose open-chain forms an aldehyde group, the test yields a positive result when glucose is present in the analyte.

Detailed explanation-5: -When glucose is mixed with Benedict’s reagent and heated, a reduction reaction causes the Benedict’s reagent to change color. The color varies from green to dark red (brick) or rusty-brown, depending on the amount of and type of sugar. Glucose never gives violet colour precipitate with Benedict’s solution.