A : The gravitational force between the gas molecules is ineffective due to extremely small size and very high speed.
R : No force of interaction acts between molecules of an ideal gas.

Options

A. If both Assertion & Reason are true and the reason is the correct explanation of the assertion, then Mark (1)
B. If both Assertion & Reason are true but the reason is not the correct explanation of the assertion, then mark (2)
C. If Assertion is true statement but Reason is false, then mark (3)
D. If both Assertion and Reason are false statements, then mark (4).

Answer

To solve the given assertion and reason problem, we will analyze both statements step by step.

### Step 1: Analyze the Assertion
The assertion states: "The gravitational force between the gas molecules is ineffective due to extremely small size and very high speed."

1. **Understanding Gravitational Force**: The gravitational force between two molecules is given by the formula:
\[ F = \frac{G \cdot m_1 \cdot m_2}{r^2} \]
where \( G \) is the gravitational constant, \( m_1 \) and \( m_2 \) are the masses of the molecules, and \( r \) is the distance between them.

2. **Small Masses**: The masses of gas molecules are very small (usually expressed in atomic mass units, AMUs). When converted to kilograms, these values are on the order of \( 10^{-27} \) kg.

3. **Large Distances**: The distance \( r \) between gas molecules is typically on the order of angstroms (10^-10 meters). This large distance further reduces the gravitational force.

4. **Conclusion**: Given the small masses and the large distances, the gravitational force between gas molecules is indeed negligible. Additionally, the high speed of gas molecules contributes to the ineffectiveness of any gravitational attraction.

**Conclusion for Assertion**: The assertion is **True**.

### Step 2: Analyze the Reason
The reason states: "No force of interaction acts between molecules of an ideal gas."

1. **Ideal Gas Assumption**: In the kinetic theory of gases, an ideal gas is defined as a gas where the molecules do not exert any forces on each other except during elastic collisions. This means that intermolecular forces (like gravitational force) are considered negligible.

2. **Implication**: The statement is true in the context of ideal gases, where we assume that there are no attractive or repulsive forces acting between the molecules.

**Conclusion for Reason**: The reason is also **True**.

### Step 3: Relationship Between Assertion and Reason
1. **Connection**: While both the assertion and reason are true, the reason does not directly explain the assertion. The assertion focuses on the gravitational force being ineffective due to size and speed, while the reason discusses the absence of interaction forces in an ideal gas.

2. **Final Conclusion**: Both the assertion and the reason are true, but the reason is not the correct explanation for the assertion.

### Final Answer
Both A and R are true, but R is not the correct explanation of A.

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