Which of the following statements is not true ?

Options

A. Glucose and fructose both are monosaccharides
B. The natural glucose and fructose are D-forms.
C. The solution having equal molecules of D-glucose and D-fructose is termed as invert sugar.
D. Aldohexoses exist in `2^(6)` optical forms

Explanation

To determine which statement is not true, we will analyze each statement one by one.

### Step 1: Analyze the first statement
**Statement:** Glucose and fructose both are monosaccharides.
**Analysis:**
- Glucose and fructose are both simple sugars, classified as monosaccharides.
- They share the same molecular formula, C6H12O6.
**Conclusion:** This statement is true.

### Step 2: Analyze the second statement
**Statement:** The natural glucose and fructose are D forms.
**Analysis:**
- The D form of sugars is defined by the position of the hydroxyl group on the penultimate carbon atom.
- In both glucose and fructose, the hydroxyl group is on the right side in their D forms.
**Conclusion:** This statement is true.

### Step 3: Analyze the third statement
**Statement:** The solution having equal molecules of D-glucose and D-fructose is termed as invert sugar.
**Analysis:**
- Invert sugar is produced by hydrolyzing sucrose, which breaks down into equal parts of glucose and fructose.
- Therefore, a solution with equal amounts of D-glucose and D-fructose is indeed termed invert sugar.
**Conclusion:** This statement is true.

### Step 4: Analyze the fourth statement
**Statement:** Aldohexoses exist in 2 raised to the power 6 optical centers.
**Analysis:**
- Aldohexoses are sugars with six carbon atoms and contain multiple chiral centers.
- For aldohexoses, there are 4 chiral centers. The number of optical isomers is calculated using the formula 2^n, where n is the number of chiral centers.
- Thus, for 4 chiral centers, the number of optical isomers is 2^4 = 16, not 2^6.
**Conclusion:** This statement is not true.

### Final Conclusion
The statement that is not true is the fourth one: "Aldohexoses exist in 2 raised to the power 6 optical centers."

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