What are reducing and non-reducing sugars ? What is the structural feature characterising reducing sugars ? What is an invert sugar ?

Explanation

### Step-by-Step Text Solution

1. **Definition of Reducing and Non-Reducing Sugars**:
- **Reducing Sugars**: These are carbohydrates that can reduce certain chemical reagents, such as Benedict's solution or Tollens' reagent. This ability is due to the presence of a free aldehyde group (-CHO) or a free ketone group (C=O) in their structure.
- **Non-Reducing Sugars**: These are carbohydrates that do not have the ability to reduce chemical reagents like Benedict's or Tollens' reagent. They lack a free aldehyde or ketone group, which is essential for the reducing property.

2. **Structural Features Characterizing Reducing Sugars**:
- Reducing sugars possess a free aldehyde group (-CHO) or a free ketone group (C=O) in their molecular structure. This allows them to act as reducing agents. Common examples of reducing sugars include glucose and fructose.
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