What is laevorotatory

Options

A. Fructose
B. Glucose
C. Maltose
D. Sucrose.

Answer

### Step-by-Step Solution:

1. **Understanding Optical Activity**:
- Optical activity refers to the ability of a substance to rotate the plane of polarized light. This property is commonly observed in chiral compounds, which are molecules that cannot be superimposed on their mirror images.

2. **Classification of Sugars**:
- Sugars, particularly monosaccharides and disaccharides, can be classified based on their optical activity. They are categorized into two types: D-sugars (dextrorotatory) and L-sugars (levorotatory).

3. **Dextrorotatory vs. Levorotatory**:
- Dextrorotatory (D-sugars) are those that rotate polarized light to the right (clockwise).
- Levorotatory (L-sugars) are those that rotate polarized light to the left (counterclockwise).

4. **Example of Levorotatory Sugar**:
- An example of a levorotatory sugar is fructose. This sugar is known to rotate polarized light to the left, hence it is classified as an L-sugar.

5. **Comparison with Other Sugars**:
- Other sugars mentioned, such as glucose, maltose, and sucrose, are classified as D-sugars because they rotate polarized light to the right.

6. **Historical Context**:
- Fructose was historically referred to as "libulose" because of its levorotatory nature, indicating its ability to rotate light to the left.

### Final Answer:
Levorotatory refers to substances, particularly sugars, that rotate the plane of polarized light to the left. An example of a levorotatory sugar is fructose.

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