Biomolecules Question 187
Question: Which of the following pairs can be distinguished by Fehling’s solution-
Options:
A) Glucose and fructose
B) Glucose and sucrose
C) Methanal and ethanol
D) Hydroxypropanone and benzaldehyde.
Show Answer
Answer:
Correct Answer: B
Solution:
[b] Glucose is a hemiacetal, so in presence of a base (alkaline medium is provided by Fehling’s solution) it can develop -CHO group in the form of open chain structure which responds Fehling’s solution. Sucrose is a glycoside (acetal), i.e. its hemiacetal OH groups (one due to glucose and another due to fructose) are not free, so it can’t attain -CHO group. Hence it will not respond Fehling’s solution.
BETA
