A: Number of atoms in 2 mole of `NH_(3)` is equal to number of atoms in 4 mole of `CH_(4)`
R: Both are chemically similar species.

Options

A. If both Assertion & Reason are true and the reason is the correct explanation of the assertion
B. If both Assertion & Reason are true but the reason is not the correct explanation of the assertion
C. If Assertion is true statement but Reason is false
D. If both Assertion and Reason are false statements

Answer

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

### Step-by-Step Solution:

**Step 1: Analyze the Assertion**
- The assertion states that the number of atoms in 2 moles of \( NH_3 \) is equal to the number of atoms in 4 moles of \( CH_4 \).
- We need to calculate the number of atoms in both compounds.

**Step 2: Calculate the Number of Atoms in \( NH_3 \)**
- Each molecule of \( NH_3 \) contains 1 nitrogen atom and 3 hydrogen atoms, totaling 4 atoms.
- For 2 moles of \( NH_3 \):
\[ \text{Number of molecules} = 2 \, \text{moles} \times 6.022 \times 10^{23} \, \text{molecules/mole} = 1.2044 \times 10^{24} \, \text{molecules} \]
- Therefore, the total number of atoms in 2 moles of \( NH_3 \) is:
\[ \text{Total atoms} = 1.2044 \times 10^{24} \, \text{molecules} \times 4 \, \text{atoms/molecule} = 4.8176 \times 10^{24} \, \text{atoms} \]

**Step 3: Calculate the Number of Atoms in \( CH_4 \)**
- Each molecule of \( CH_4 \) contains 1 carbon atom and 4 hydrogen atoms, totaling 5 atoms.
- For 4 moles of \( CH_4 \):
\[ \text{Number of molecules} = 4 \, \text{moles} \times 6.022 \times 10^{23} \, \text{molecules/mole} = 2.4088 \times 10^{24} \, \text{molecules} \]
- Therefore, the total number of atoms in 4 moles of \( CH_4 \) is:
\[ \text{Total atoms} = 2.4088 \times 10^{24} \, \text{molecules} \times 5 \, \text{atoms/molecule} = 1.2044 \times 10^{25} \, \text{atoms} \]

**Step 4: Compare the Number of Atoms**
- From the calculations:
- Number of atoms in 2 moles of \( NH_3 \) = \( 4.8176 \times 10^{24} \)
- Number of atoms in 4 moles of \( CH_4 \) = \( 1.2044 \times 10^{25} \)
- Clearly, \( 4.8176 \times 10^{24} \neq 1.2044 \times 10^{25} \).
- Therefore, the assertion is **false**.

**Step 5: Analyze the Reason**
- The reason states that both \( NH_3 \) and \( CH_4 \) are chemically similar species.
- However, \( NH_3 \) (ammonia) contains nitrogen, while \( CH_4 \) (methane) contains carbon. They belong to different groups in the periodic table and have different bonding characteristics.
- Thus, the reason is also **false**.

### Conclusion:
Both the assertion and the reason are false. Therefore, the correct option is that both statements are false.