Pure water is a non-conductor of electricity but can be made conductor by adding to it

Options

A. sugar
B. drops of oil
C. salt
D. pieces of wood

Explanation

To solve the question "Pure water is a non-conductor of electricity but can be made a conductor by adding to it," we need to identify the correct substance that can be added to pure water to make it conductive.

### Step-by-Step Solution:

1. **Understand the Nature of Pure Water**:
- Pure water (distilled water) does not conduct electricity because it lacks free ions.

**Hint**: Remember that the conductivity of a solution depends on the presence of ions.

2. **Identify Possible Additives**:
- We are given several options: sugar, drop of oil, salt, and a piece of wood.

**Hint**: Think about which of these substances can dissociate into ions when dissolved in water.

3. **Analyze Each Option**:
- **Sugar**: When sugar dissolves in water, it does not produce ions; it remains as neutral molecules.
- **Drop of Oil**: Oil does not dissolve in water and does not produce ions.
- **Salt (NaCl)**: When salt dissolves in water, it dissociates into sodium ions (Na⁺) and chloride ions (Cl⁻), which can carry electric current.
- **Piece of Wood**: Wood is an insulator and does not contribute to conductivity.

**Hint**: Consider the chemical properties of each option and their behavior in water.

4. **Conclusion**:
- The only substance from the options that can be added to pure water to make it a conductor is salt (NaCl). When salt is added to pure water, it dissolves and releases ions, allowing the solution to conduct electricity.

**Final Answer**: The correct answer is **salt**.