Which one of the following bonds produces a solid that reflects light in the visible region and whose electrical conductivity decreases with temperature and has high melting point?

Options

A. metaallic bonding
B. vander Waal's bonding
C. ionic bonding
D. Covalent bonding

Answer

To solve the question, we need to analyze the properties of different types of bonds and identify which one matches the criteria given in the question.

### Step-by-Step Solution:

1. **Identify the Properties Required:**
The question specifies three properties of the solid:
- Reflects light in the visible region.
- Electrical conductivity decreases with temperature.
- High melting point.

2. **Analyze Different Types of Bonds:**
- **Ionic Bonds:** Typically form crystalline solids that do not reflect light well and have high melting points. However, their electrical conductivity usually increases with temperature.
- **Covalent Bonds:** Generally form non-metallic solids that do not conduct electricity and may not reflect light in the visible region.
- **Metallic Bonds:** Metals typically reflect light due to their free electrons, exhibit high melting points, and their electrical conductivity decreases with increasing temperature.

3. **Evaluate Metallic Bonds:**
- **Reflects Light:** Metals have free electrons that can reflect visible light, making them appear shiny.
- **Electrical Conductivity:** In metals, as temperature increases, the vibrations of the lattice structure increase, which can scatter the electrons and decrease conductivity.
- **High Melting Point:** Most metals have high melting points due to the strong metallic bonding forces.

4. **Conclusion:**
Based on the analysis, the type of bond that produces a solid with the specified properties is the **metallic bond**.

### Final Answer:
The bond that produces a solid that reflects light in the visible region, has electrical conductivity that decreases with temperature, and has a high melting point is the **metallic bond**.

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