Question 1

Which of the following best explains why honey (image 2) tastes sweeter than ripe grapes (image 1)?

Accepted Answer

Honey contains a higher proportion of fructose, which is sweeter than glucose.

Question 2

Given the molecular formula $$C_6H_{12}O_6$, which of the following statements is correct regarding glucose and fructose?

Accepted Answer

Both are monosaccharides with the same molecular formula but different structural arrangements.

Question 3

Which functional groups are present in the open-chain structure of glucose?

Accepted Answer

Aldehyde group and multiple hydroxyl groups

Question 4

Which reaction is used to distinguish between glucose and fructose based on their functional groups?

Accepted Answer

Reaction with bromine water, which oxidizes the aldehyde group in glucose but not the ketone group in fructose.

Question 5

In the experiment shown in images 3, 4, and 5, what is the chemical process occurring when the solution changes from blue to brick-red upon heating with glucose?

Accepted Answer

The aldehyde group in glucose reduces $$Cu^{2+} to$$ $$Cu_2O ($$brick-red precipitate).

Question 6

Which of the following best describes the result of the Tollens' test (images 6 and 7) with glucose?

Accepted Answer

A silver mirror forms due to the reduction of $$Ag^+ to $$metallic silver by the aldehyde group in glucose.

Question 7

Why can fructose also give a positive Tollens' test, even though it is a ketose?

Accepted Answer

In basic solution, fructose is converted to glucose and mannose, which contain an aldehyde group.

Question 8

Which chemical equation represents the fermentation of glucose to ethanol?

Accepted Answer

$$C_6H_{12}O_6$ \xrightarrow{enzyme} 2C_2H_5OH + 2CO_2$$

Question 9

What is the main reason why glucose solutions (such as the one in image 8) are used in hospitals to treat hypoglycemia?

Accepted Answer

Glucose is rapidly absorbed and utilized by the body to quickly raise blood sugar levels.

Question 10

Which of the following statements about the reaction of glucose with bromine water is correct?

Accepted Answer

The aldehyde group in glucose is oxidized to a carboxylic acid.

Question 11

Which structural feature distinguishes glucose from fructose in their open-chain forms?

Accepted Answer

Glucose contains an aldehyde group, while fructose contains a ketone group.

Question 12

Which of the following best describes the role of the hemiacetal hydroxyl group in glucose?

Accepted Answer

It can react with alcohols to form acetals (glycosides).

Question 13

Why is it important to control the temperature during fermentation of glucose?

Accepted Answer

High temperatures can denature the enzymes required for fermentation.

Question 14

Which of the following is NOT a typical application of glucose in industry or medicine?

Accepted Answer

Used as a primary ingredient in the production of plastics.

Question 15

Which of the following best explains why both glucose and fructose can form a blue solution with $$Cu(OH)_2 at $$room temperature?

Accepted Answer

Both contain multiple hydroxyl groups that can complex with $$Cu^{2+}$$ ions.

Question 16

Which of the following reactions is used to distinguish between an aldehyde and a ketone group in carbohydrates?

Accepted Answer

Reaction with bromine water, which oxidizes aldehydes but not ketones.

Glucose and Fructose: Structure, Properties, and Applications

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