Among the following, which have highest melting point?

Options

A. Ionic solids
B. Pseudo solids
C. Molecular solids
D. Amorphous solids

Explanation

To determine which among the given solids has the highest melting point, we need to analyze the types of solids mentioned and their properties.

### Step-by-Step Solution:

1. **Identify the Types of Solids**:
- The question refers to different types of solids, which typically include ionic solids, molecular solids, pseudo-solids, and morphosolids.

2. **Understand Ionic Solids**:
- Ionic solids consist of positive and negative ions held together by strong electrostatic forces of attraction (ionic bonds). These strong interactions result in a high melting point because a significant amount of energy is required to break these bonds.

3. **Evaluate Pseudo-Solids**:
- Pseudo-solids may appear solid but behave like liquids. Their structure does not have strong intermolecular forces, leading to a lower melting point.

4. **Analyze Molecular Solids**:
- Molecular solids are held together by weaker intermolecular forces (like van der Waals forces or hydrogen bonds). These forces are relatively easy to overcome, resulting in lower melting points compared to ionic solids.

5. **Consider Morphosolids**:
- Morphosolids, such as glass, do not have a definite melting point. They soften over a range of temperatures, which means they do not have a high melting point in the traditional sense.

6. **Conclusion**:
- Among the types of solids discussed, ionic solids have the highest melting point due to the strong electrostatic forces that hold the ions together. Therefore, the solid with the highest melting point is the ionic solid.

### Final Answer:
The solid with the highest melting point among the options provided is the **ionic solid**.