Which of the following compound is used in visualisation of DNA fragments in gel electrophoresis?

Options

A. Hexachlorobenzene
B. Silver bromode
C. Ethyl chloride
D. Ethidium bromide

Answer

To solve the question "Which of the following compound is used in visualization of DNA fragments in gel electrophoresis?", we can follow these steps:

### Step 1: Understand the Context
Gel electrophoresis is a technique used to separate DNA fragments based on their size. After separation, it is important to visualize these fragments to analyze the results.

**Hint:** Recall that DNA fragments are not visible to the naked eye after electrophoresis.

### Step 2: Identify the Need for Visualization
Since DNA fragments are transparent and dissolve in the buffer used during electrophoresis, we need a method to visualize them. This is typically done using a fluorescent dye.

**Hint:** Think about substances that can bind to DNA and emit fluorescence under UV light.

### Step 3: Evaluate the Options
The options provided are:
- Hexachlorobenzene
- Silver chromite
- Ethyl chloride
- Ethidium bromide

**Hint:** Consider which of these compounds is known for its interaction with DNA.

### Step 4: Analyze Each Option
1. **Hexachlorobenzene**: This is a chemical compound that does not have any known application in DNA visualization.
2. **Silver chromite**: This is not used for visualizing DNA in gel electrophoresis.
3. **Ethyl chloride**: This is a solvent and does not interact with DNA for visualization purposes.
4. **Ethidium bromide**: This is a well-known intercalating agent that binds to DNA and fluoresces under UV light.

**Hint:** Look for the compound that is specifically mentioned in scientific literature for DNA visualization.

### Step 5: Conclusion
Based on the analysis, the correct answer is **Ethidium bromide**. It is widely used in laboratories for the visualization of DNA fragments after gel electrophoresis due to its ability to intercalate with DNA and emit fluorescence when exposed to UV light.

**Final Answer:** Ethidium bromide