10 moles `SO_(2)` and 15 moles `O_(2)` were allowed to react over a suitable catalyst. 8 moles of `SO_(3)` were formed. The remaining moles of `SO_(2)` and `O_(2)` respectively are -

Options

A. 2 moles, 11 moles
B. 2 moles, 8 moles
C. 4 moles, 5 moles
D. 8 moles, 2 moles

Explanation

To solve the problem, we need to analyze the reaction between sulfur dioxide (SO₂) and oxygen (O₂) to form sulfur trioxide (SO₃). The balanced chemical equation for this reaction is:

\[ 2 \text{SO}_2 + \text{O}_2 \rightarrow 2 \text{SO}_3 \]

### Step-by-Step Solution:

1. **Identify Initial Moles:**
- Initial moles of SO₂ = 10 moles
- Initial moles of O₂ = 15 moles

2. **Determine Moles of SO₃ Formed:**
- Moles of SO₃ formed = 8 moles

3. **Relate Moles of Reactants to Products:**
- According to the balanced equation, 2 moles of SO₂ react with 1 mole of O₂ to produce 2 moles of SO₃.
- Therefore, if 8 moles of SO₃ are produced, we can set up the following relationships:
- Let \( x \) be the moles of O₂ consumed.
- From the equation, for every 2 moles of SO₂ consumed, 1 mole of O₂ is consumed.
- Thus, if 8 moles of SO₃ are produced, then:
\[ 2x = 8 \quad \Rightarrow \quad x = 4 \]
- This means 4 moles of O₂ were consumed.

4. **Calculate Remaining Moles of SO₂ and O₂:**
- Moles of SO₂ consumed:
- From the stoichiometry, since 2 moles of SO₂ produce 2 moles of SO₃, the moles of SO₂ consumed are also 8 moles.
- Remaining moles of SO₂:
\[ \text{Remaining SO}_2 = \text{Initial SO}_2 - \text{Consumed SO}_2 = 10 - 8 = 2 \text{ moles} \]
- Remaining moles of O₂:
\[ \text{Remaining O}_2 = \text{Initial O}_2 - \text{Consumed O}_2 = 15 - 4 = 11 \text{ moles} \]

5. **Final Answer:**
- Remaining moles of SO₂ = 2 moles
- Remaining moles of O₂ = 11 moles

### Summary:
- The remaining moles of SO₂ are 2 moles, and the remaining moles of O₂ are 11 moles.