Properties of substances W, X, Y and Z are listed below:
W: A liquid metal
X: A liquid non-metal
Y: A gaseous non-metal
Z: A non-metal which conducts electricity
W, X, Y and Z are respectively

Options

A. Iron, iodine, hydrogen and oxygen
B. Gold, sulphur, chlorine and hydrogen
C. Copper, phosphorus, nitrogen and carbon
D. Mercury, bromine, oxygen and graphite.

Answer

To determine the substances W, X, Y, and Z based on the given properties, we can analyze each property step-by-step.

### Step-by-Step Solution:

1. **Identify W (Liquid Metal)**:
- The only known liquid metal at room temperature is **Mercury (Hg)**.
- Other metals like iron, gold, and copper are solid at room temperature.
- **Conclusion**: W = Mercury.

2. **Identify X (Liquid Non-Metal)**:
- Among non-metals, **Bromine (Br)** is the only liquid at room temperature.
- Other non-metals like iodine, sulfur, and phosphorus are solids at room temperature.
- **Conclusion**: X = Bromine.

3. **Identify Y (Gaseous Non-Metal)**:
- There are several gaseous non-metals, including **Hydrogen (H)**, **Chlorine (Cl)**, **Nitrogen (N)**, and **Oxygen (O)**.
- Since the question does not specify further, any of these could fit, but for a common example, we can take **Oxygen (O)**, which is essential for respiration.
- **Conclusion**: Y = Oxygen.

4. **Identify Z (Non-Metal that Conducts Electricity)**:
- The non-metal that is known to conduct electricity is **Graphite**, a form of carbon.
- Other non-metals like sulfur and phosphorus do not conduct electricity.
- **Conclusion**: Z = Graphite.

### Final Summary:
- W = Mercury (Liquid Metal)
- X = Bromine (Liquid Non-Metal)
- Y = Oxygen (Gaseous Non-Metal)
- Z = Graphite (Non-Metal that Conducts Electricity)