Assertion : Liquids and solids are hard to compress .
Reason : Magnitude of the repulsive forces between the molecules rises very rapidly as the distance separating the molecules decreases .

Options

A. both assertion and reason are true and reason is the correct explanation of assertion .
B. both assertion and reason are true but reason is not the correct explanation of assertion .
C. assertion is true but reason is false .
D. both assertion and reason are false .

Explanation

To solve the assertion and reason question, we will analyze both the assertion and the reason step by step.

### Step 1: Understand the Assertion
The assertion states that "Liquids and solids are hard to compress."
- **Explanation**: This is true because both liquids and solids have closely packed molecules. In solids, the molecules are arranged in a fixed structure, while in liquids, they are still close together but can move past one another. Due to this close packing, there is very little space for the molecules to move into when pressure is applied, making them hard to compress.

### Step 2: Understand the Reason
The reason states that "Magnitude of the repulsive forces between the molecules rises very rapidly as the distance separating the molecules decreases."
- **Explanation**: This statement is also true. When molecules are pushed closer together, the forces that repel them (due to electron cloud interactions) become stronger. This repulsion is a result of the electron clouds of the molecules overlapping, which leads to an increase in repulsive forces. As the distance between the molecules decreases, these repulsive forces increase significantly, contributing to the resistance against compression.

### Step 3: Connect the Assertion and Reason
Now we need to determine if the reason provided correctly explains the assertion.
- **Explanation**: The reason explains why liquids and solids are hard to compress. The repulsive forces that increase as molecules are pushed closer together contribute to their resistance to compression. Therefore, the reason supports the assertion.

### Conclusion
Both the assertion and the reason are true, and the reason is the correct explanation of the assertion.

### Final Answer
Both the assertion and reason are true, and the reason is the correct explanation of the assertion.

---