Assertion : The molecules of a monatomic gas has three degrees freedom.
Reason : The molecules of a diatomic gas has five degrees of freedom.

Options

A. Both assertion and reson are true and reason is the correct explanation of assertion
B. Both assetion and reason are true but reason is not the correct explanation of assertion
C. Assertion is true but reason is false
D. Both assetion and reason are flase

Answer

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

### Step 1: Understanding Degrees of Freedom
- Degrees of freedom (DOF) refer to the number of independent ways in which a system can possess energy. For gases, this typically includes translational, rotational, and vibrational motions.

**Hint**: Remember that degrees of freedom are related to the types of motion available to the molecules.

### Step 2: Degrees of Freedom for Monatomic Gas
- A monatomic gas consists of single atoms (e.g., noble gases like helium, neon).
- Each atom can move in three-dimensional space, which gives it three translational degrees of freedom: movement along the x-axis, y-axis, and z-axis.

**Hint**: For monatomic gases, focus on translational motion only.

### Step 3: Degrees of Freedom for Diatomic Gas
- A diatomic gas consists of molecules made up of two atoms (e.g., oxygen, nitrogen).
- These molecules have three translational degrees of freedom (movement in x, y, and z directions) and can also rotate about two axes (perpendicular to the line connecting the two atoms). This gives a total of five degrees of freedom (3 translational + 2 rotational).

**Hint**: Consider both translational and rotational motions for diatomic gases.

### Step 4: Evaluating the Assertion
- The assertion states that "the molecules of a monatomic gas have three degrees of freedom." This is true based on our analysis.

**Hint**: Confirm the number of degrees of freedom for monatomic gases.

### Step 5: Evaluating the Reason
- The reason states that "the molecules of a diatomic gas have five degrees of freedom." This is also true based on our analysis.

**Hint**: Verify the total degrees of freedom for diatomic gases.

### Step 6: Conclusion
- Both the assertion and the reason are true. However, the reason does not explain the assertion directly. The assertion is about monatomic gases, while the reason discusses diatomic gases.

**Final Answer**: Both the assertion and reason are true, but the reason is not the correct explanation of the assertion. Therefore, the correct option is B.