Which of the following statements is not true about glucose?
Which of the following statements is not true about glucose?
Show Hint
- It is an aldose.
- On heating with HI it forms n-hexane.
- It exists in furanose form.
It does not give Schiff's test.
The Correct Option is A
Approach Solution - 1
The question asks which statement about glucose is not true. Let's evaluate each option:
- Glucose is an aldose: Glucose is indeed an aldose, as it contains an aldehyde group at the first carbon. Hence, this statement is true.
- On heating with HI, glucose forms n-hexane: This is a characteristic reaction where the entire glucose molecule reduces to n-hexane when treated with hydrogen iodide. Thus, this statement is also true.
- It exists in furanose form: Glucose typically forms a pyranose ring when cyclized, not a furanose form. Therefore, this statement is not true about glucose.
- It does not give Schiff's test: Glucose does not give a positive Schiff's test because while it contains an aldehyde group, it forms a stable cyclic hemiacetal form that typically doesn't react with Schiff's reagent. Hence, this statement is true.
Considering the analysis above, the statement that is not true about glucose is: It exists in furanose form.
Approach Solution -2
Step 1: Understanding glucose's properties. Glucose is an aldose (option A) and forms n-hexane on heating with HI (option B). It can exist in the furanose form (option C) as well.
Step 2: Schiff's test. Glucose, being an aldehyde, will give a positive Schiff's test, which detects aldehydes.
Step 3: Conclusion. Thus, the statement that glucose does not give Schiff's test is incorrect, corresponding to option (D).
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