Assertion : One mole of helium atoms should occupy 22.4 litres volume at STP
Reason : Taking 31 pm as radius of helium atoms, if we pack together a mole of helium atoms, the mole of atoms should have a volume of 22.4 litre

Options

A. Both A and R are true and R is the correct explanation of A
B. Both A and R are true but R is not a correct explanation of A
C. A is true but R is false
D. A is false but R is true

Answer

To solve the question, we need to analyze both the assertion and the reason provided.

### Step 1: Evaluate the Assertion
The assertion states that "One mole of helium atoms should occupy 22.4 liters volume at STP."

- At Standard Temperature and Pressure (STP), one mole of any ideal gas occupies 22.4 liters. Helium, being a noble gas and behaving closely to an ideal gas, also follows this rule.

Thus, the assertion is **True**.

### Step 2: Evaluate the Reason
The reason states, "Taking 31 pm as the radius of helium atoms, if we pack together a mole of helium atoms, the mole of atoms should have a volume of 22.4 liters."

- The volume occupied by a mole of helium atoms is derived from the ideal gas law and is not directly related to the atomic radius of helium. The atomic radius (31 pm) does not determine the volume occupied by a mole of helium atoms when they behave as a gas.

Therefore, the reason is **False**.

### Conclusion
- Assertion: True
- Reason: False

### Final Answer
The assertion is true, but the reason is false.

---