The statement which is incorrect withrespect to glucose is

Options

A. Reduces Felhing's solution and Tollen's reagent
B. Reacts with hydroxylamine to form an oxime
C. Adds a molecule of hydrogen cyanide to give cyanohydrin
D. Gives yellow ppt with I2 in alkali

Answer

To solve the question regarding which statement about glucose is incorrect, we can analyze each statement one by one.

### Step-by-Step Solution:

1. **Identify the Statements**: We need to evaluate the following statements about glucose:
- Statement 1: Glucose reduces Fehling's solution and Tollen's reagent.
- Statement 2: Glucose reacts with hydroxylamine to form oxime.
- Statement 3: Glucose adds a molecule of hydrogen cyanide to give cyanohydrin.
- Statement 4: Glucose gives a yellow precipitate with iodine in alkaline medium.

2. **Evaluate Statement 1**:
- Glucose is a monosaccharide with an aldehyde group.
- It can reduce Fehling's solution (which contains copper ions) and Tollen's reagent (which contains silver ions).
- **Conclusion**: This statement is **correct**.

3. **Evaluate Statement 2**:
- The aldehyde group in glucose can react with hydroxylamine to form an oxime.
- **Conclusion**: This statement is **correct**.

4. **Evaluate Statement 3**:
- Glucose can react with hydrogen cyanide (HCN) to form cyanohydrin due to the presence of the aldehyde group.
- **Conclusion**: This statement is **correct**.

5. **Evaluate Statement 4**:
- The yellow precipitate with iodine in alkaline medium is characteristic of compounds containing a methyl ketone group (like acetone), known as the iodoform test.
- Glucose does not contain a methyl ketone group and therefore does not give a yellow precipitate with iodine in alkaline medium.
- **Conclusion**: This statement is **incorrect**.

6. **Final Answer**: The incorrect statement regarding glucose is **Statement 4**.