Select the correct statements.
(A) Crystalline solids have long range order.
(B) Crystalline solids are isotropic.
(C) Amorphous solid are sometimes called pseudo solids.
(D) Amorphous solids soften over a range of temperatures.
(E) Amorphous solids have a definite heat of fusion.
Choose the most appropriate answer from the options given below.

Options

A. (A), (B), (E) only
B. (B), (D) only
C. (C), (D) only
D. (A), (C), (D) only

Answer

To solve the question, we will analyze each statement one by one to determine which ones are correct.

**Step 1: Analyze Statement (A)**
**Statement (A)**: Crystalline solids have long range order.
- **Explanation**: Crystalline solids are characterized by a well-defined, repeating arrangement of atoms, ions, or molecules, which extends over long distances. This means they have both short-range and long-range order.
- **Conclusion**: This statement is **True**.

**Step 2: Analyze Statement (B)**
**Statement (B)**: Crystalline solids are isotropic.
- **Explanation**: Crystalline solids are actually **anisotropic**, meaning their physical properties vary depending on the direction in which they are measured. This is due to the ordered arrangement of particles.
- **Conclusion**: This statement is **False**.

**Step 3: Analyze Statement (C)**
**Statement (C)**: Amorphous solids are sometimes called pseudo solids.
- **Explanation**: Amorphous solids lack a long-range order and are often referred to as pseudo solids or supercooled liquids because they do not have a defined shape or structure like crystalline solids.
- **Conclusion**: This statement is **True**.

**Step 4: Analyze Statement (D)**
**Statement (D)**: Amorphous solids soften over a range of temperatures.
- **Explanation**: Amorphous solids do not have a sharp melting point; instead, they soften gradually over a range of temperatures due to their disordered structure.
- **Conclusion**: This statement is **True**.

**Step 5: Analyze Statement (E)**
**Statement (E)**: Amorphous solids have a definite heat of fusion.
- **Explanation**: Amorphous solids do not have a definite heat of fusion because they do not melt sharply at a specific temperature. This property is characteristic of crystalline solids.
- **Conclusion**: This statement is **False**.

**Final Conclusion**: The correct statements are (A), (C), and (D). Therefore, the most appropriate answer is option 4, which includes statements A, C, and D.

### Summary of Correct Statements:
- (A) Crystalline solids have long range order. **(True)**
- (B) Crystalline solids are isotropic. **(False)**
- (C) Amorphous solids are sometimes called pseudo solids. **(True)**
- (D) Amorphous solids soften over a range of temperatures. **(True)**
- (E) Amorphous solids have a definite heat of fusion. **(False)**