To solve the question regarding the properties of substance X, we need to analyze the information given about its melting point and boiling point, and then evaluate the statements provided.
### Step-by-Step Solution:
1. **Identify the States of Matter**:
- The melting point of substance X is -10°C. This means:
- Below -10°C, substance X is in a solid state.
- At -10°C, it starts to melt into a liquid.
- Above -10°C and below 115°C, it is in a liquid state.
- The boiling point of substance X is 115°C. This means:
- Above 115°C, substance X is in a gaseous state.
- At 115°C, it starts to boil and turn into gas.
- Below 115°C, it remains in a liquid state (if above -10°C).
2. **Analyze Each Statement**:
- **Statement 1**: The particles of X have minimum inter-particle forces at -20°C.
- At -20°C, substance X is solid (since it is below -10°C). In solids, inter-particle forces are maximum, not minimum. This statement is **incorrect**.
- **Statement 2**: The particles of X have maximum inter-particle distance at 150°C.
- At 150°C, substance X is in a gaseous state. In gases, particles are far apart, so this statement is **correct**.
- **Statement 3**: The particles of X have definite volume but not definite shape at -5°C.
- At -5°C, substance X is in a liquid state. Liquids have a definite volume but take the shape of their container, so this statement is **correct**.
- **Statement 4**: The particles of X do not have definite shape and definite volume at 120°C.
- At 120°C, substance X is in a gaseous state. Gases do not have a definite shape or volume, so this statement is **correct**.
3. **Conclusion**:
- The only statement that is incorrect is **Statement 1**. Therefore, the answer to the question is that the first option is incorrect regarding the particles of X.
### Final Answer:
The incorrect statement regarding the particles of substance X is: **The particles of X have minimum inter-particle forces at -20°C.**
