Question

question 4
there are only two outcomes for a color change for the benedicts reaction and that is blue if negative and red if positive
true
false
question 5
all sugars will give a positive result for the benedicts reaction when heated
true
false
question 6
which of the following is a disaccharide made by the covalent bonding of the two monosaccharides glucose and fructose?
sucrose
lactose
galactose
mannose
question 7
this disaccharide is found in milk and is formed from glucose and galactose
sucrose
lactose
fructose
maltose

Explanation:

• Question 4: Benedict's reaction has two main color - change outcomes. A negative result shows a blue color (due to the blue - colored copper(II) ions in the Benedict's reagent remaining unreacted), and a positive result shows a red color (due to the formation of red copper(I) oxide).
• Question 5: Not all sugars give a positive Benedict's reaction. Only reducing sugars (such as glucose, fructose, and maltose) react with Benedict's reagent upon heating to produce a color change. Non - reducing sugars like sucrose do not give a positive result without prior hydrolysis.
• Question 6: Sucrose is a disaccharide formed by the covalent bonding of glucose and fructose.
• Question 7: Lactose is a disaccharide found in milk and is formed from glucose and galactose.

Answer:

• Question 4: A. True
• Question 5: B. False
• Question 6: A. sucrose
• Question 7: B. lactose