Question

Какая реакция является качественной для глюкозы?

Answer 1

Qualitative Reaction for Glucose

A qualitative reaction refers to a chemical test that helps identify the presence or absence of a specific substance. In the case of glucose, there are several qualitative reactions that can be used to detect its presence. One commonly used test is the Benedict's test.

The Benedict's test is a qualitative reaction used to detect the presence of reducing sugars, including glucose. The test involves mixing a sample with Benedict's reagent, which is a solution containing copper sulfate, sodium carbonate, and sodium citrate. When heated, if glucose is present, it will reduce the copper sulfate to form a reddish-brown precipitate of copper(I) oxide.

Here is a step-by-step procedure for the Benedict's test:

1. Take a small amount of the sample (liquid or solid) suspected to contain glucose. 2. Add an equal volume of Benedict's reagent to the sample. 3. Heat the mixture in a water bath or gently boil it for a few minutes. 4. Observe the color change in the mixture. If glucose is present, the solution will change from blue to green, yellow, orange, or brick-red, depending on the concentration of glucose.

It's important to note that the intensity of the color change can vary depending on the amount of glucose present. A higher concentration of glucose will result in a more intense color change.

Please keep in mind that the Benedict's test is just one of several qualitative reactions that can be used to detect glucose. Other tests, such as the Fehling's test and the Barfoed's test, can also be used for this purpose. However, the Benedict's test is commonly used due to its simplicity and reliability.

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