Which of the following statements are correct for glucose?

Options

A. It gives positive test with Schiff's reagent
B. It reacts with `NaHSO_3` and `NH_3`
C. Pentaacetate derivative of glucose does not react with `H_2 N-OH`
D. It gives positive test with Fehling solution

Answer

To determine which statements are correct for glucose, we will analyze each statement one by one.

### Step 1: Analyze the first statement
**Statement 1:** Glucose gives a positive test with Schiff's reagent.

- **Analysis:** Schiff's reagent is used to test for the presence of aldehydes. Glucose does have an aldehyde group in its open-chain form, but it predominantly exists in a cyclic form (pyranose) in solution. Therefore, glucose does not give a positive test with Schiff's reagent.
- **Conclusion:** This statement is **incorrect**.

### Step 2: Analyze the second statement
**Statement 2:** Glucose reacts with NaHSO3 and NH3.

- **Analysis:** Glucose, while it has an aldehyde group, does not react with sodium bisulfite (NaHSO3) or ammonia (NH3) under normal conditions. These reactions are often used as evidence against the open-chain structure of glucose.
- **Conclusion:** This statement is **incorrect**.

### Step 3: Analyze the third statement
**Statement 3:** The pentaacetate derivative of glucose does not react with H2 and OH.

- **Analysis:** The pentaacetate derivative of glucose is formed when glucose reacts with acetic anhydride in the presence of pyridine. This derivative does not have a free aldehyde group, and therefore does not react with hydrogen (H2) or hydroxylamine (OH).
- **Conclusion:** This statement is **correct**.

### Step 4: Analyze the fourth statement
**Statement 4:** Glucose gives a positive test with Fehling's solution.

- **Analysis:** Fehling's solution is used to test for reducing sugars. Glucose, being a reducing sugar, reacts with Fehling's solution and produces a red precipitate of Cu2O when it oxidizes to gluconic acid.
- **Conclusion:** This statement is **correct**.

### Final Conclusion
The correct statements regarding glucose are **3 and 4**.

---