Which of the following pair give positive Tollen's Test ?

Options

A. Glucose, sucrose
B. Glucose, fructose
C. Hexanal,Acetophenone
D. Fructose,sucrose

Explanation

To determine which of the following pairs give a positive Tollen's test, we need to understand the concept of reducing and non-reducing sugars. Here’s a step-by-step solution:

### Step 1: Understand Tollen's Test
Tollen's test is used to identify reducing sugars. Reducing sugars are those that can donate electrons to another chemical species, which allows them to reduce Tollen's reagent (silver nitrate in ammonia) and produce a silver mirror on the test tube.

### Step 2: Identify Reducing Sugars
Reducing sugars typically contain either an aldehyde group (-CHO) or a free ketone group. Common examples of reducing sugars include:
- Glucose (an aldose)
- Fructose (a ketose)

Non-reducing sugars, such as sucrose, do not have a free aldehyde or ketone group and therefore do not give a positive Tollen's test.

### Step 3: Analyze the Given Options
Now, let’s analyze the pairs provided in the question (assuming pairs like glucose and sucrose, glucose and fructose, etc.):
1. **Glucose and Sucrose**: Glucose is a reducing sugar, but sucrose is a non-reducing sugar. This pair will not give a positive Tollen's test.
2. **Glucose and Fructose**: Both glucose and fructose are reducing sugars. This pair will give a positive Tollen's test.
3. **Other pairs (e.g., Hexanal and Acetophenone)**: Hexanal is an aldehyde (reducing), but acetophenone is a ketone (non-reducing). This pair will not give a positive Tollen's test.

### Step 4: Conclusion
Based on the analysis, the only pair that gives a positive Tollen's test is **Glucose and Fructose**.

### Final Answer
The correct answer is **Glucose and Fructose**.

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