Which of the following statements is not true about glucose?
(a)It is an aldohexose
(b)On heating with HI it forms n-hexane
(c)It is present in furanose form
(d)It does not give 2,4-DNP test

Options

A. It is an aldohexose
B. On heating with HI it forms n-hexane
C. It is present in furanose form
D. It does not give 2,4-DNP test

Explanation

To determine which statement about glucose is not true, let's analyze each option one by one.

### Step 1: Analyze Option (a)
**Statement:** "It is an aldohexose."
- **Explanation:** Glucose is indeed classified as an aldohexose because it contains six carbon atoms (hexose) and has an aldehyde group (aldo) at one end of the molecule.
- **Conclusion:** This statement is true.

### Step 2: Analyze Option (b)
**Statement:** "On heating with HI it forms n-hexane."
- **Explanation:** When glucose is heated with hydrogen iodide (HI), it can undergo a reduction process that converts it into n-hexane. This reaction involves the removal of the functional groups and the formation of a straight-chain alkane.
- **Conclusion:** This statement is also true.

### Step 3: Analyze Option (c)
**Statement:** "It is present in furanose form."
- **Explanation:** Glucose primarily exists in a cyclic form known as pyranose, which is a six-membered ring. The furanose form is a five-membered ring, which is not the predominant form of glucose. Therefore, this statement is incorrect.
- **Conclusion:** This statement is false.

### Step 4: Analyze Option (d)
**Statement:** "It does not give 2,4-DNP test."
- **Explanation:** The 2,4-DNP (dinitrophenylhydrazine) test is used to detect carbonyl compounds. Although glucose exists in a cyclic form, it can still give a positive test for the open-chain form. Thus, this statement is misleading as glucose can give a positive result in certain conditions.
- **Conclusion:** This statement is also true.

### Final Conclusion
The statement that is not true about glucose is **(c)** "It is present in furanose form."

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