Which of the following does not conduct electricity ?

Options

A. Lime juice
B. Salt solution
C. Pure water
D. Metal

Explanation

To determine which of the following substances does not conduct electricity, let's analyze each option provided:

1. **Lime Juice**: Lime juice is acidic in nature. Acids can dissociate into ions when dissolved in water, allowing them to conduct electricity. Therefore, lime juice can conduct electricity.

2. **Salt Solution**: A salt solution is formed when salt (sodium chloride) is dissolved in water. The salt dissociates into sodium ions (Na⁺) and chloride ions (Cl⁻), which are charged particles that can carry electric current. Thus, a salt solution can also conduct electricity.

3. **Pure Water**: Pure water is a very weak conductor of electricity. It contains very few ions, which means it does not conduct electricity well. While it can conduct some electricity, it is not a good conductor compared to the other options.

4. **Melt**: Melt refers to a melted substance, typically a metal or a solid that has been heated to become liquid. Metals are known to have free electrons that allow them to conduct electricity effectively. Therefore, melted metals can conduct electricity.

Based on the analysis above, the substance that does not conduct electricity well is **pure water**.

### Step-by-Step Solution:
1. **Identify the substances**: Lime juice, salt solution, pure water, and melt.
2. **Analyze lime juice**: Recognize that lime juice is acidic and can conduct electricity due to ionization.
3. **Analyze salt solution**: Understand that salt dissociates into ions in solution, allowing it to conduct electricity.
4. **Analyze pure water**: Note that pure water has very few ions and is a poor conductor of electricity.
5. **Analyze melt**: Recognize that melted metals have free electrons and can conduct electricity.
6. **Conclusion**: Determine that pure water is the substance that does not conduct electricity well compared to the others.