`{:(" List-I", " List-II"),((P) "Butane",(1) C_(6)H_(10)),((Q) "Hexyne",(2)C_(4)H_(10)),((R ) "Pentene", (3) C_(2)H_(2)), ((S) "Acetylene",(4) C_(5)H_(10)):}`

Options

A. P-1, Q-4, R-3, S-2
B. P-3, Q-2, R-4, S-1
C. P-2, Q-1, R-4, S-3
D. P-4, Q-2, R-1, S-3

Answer

To solve the problem, we need to match the hydrocarbons from List-I with their corresponding molecular formulas from List-II. Let's analyze each compound step by step.

### Step 1: Identify the hydrocarbons and their types
1. **Butane** - This is an alkane.
2. **Hexyne** - This is an alkyne.
3. **Pentene** - This is an alkene.
4. **Acetylene** - This is also an alkyne (specifically, it is the common name for ethyne).

### Step 2: Determine the number of carbon atoms and their formulas
1. **Butane (C4H10)**:
- The prefix "but" indicates 4 carbon atoms.
- The general formula for alkanes is CnH2n + 2.
- For butane: C4H(2*4) + 2 = C4H10.

2. **Hexyne (C6H10)**:
- The prefix "hex" indicates 6 carbon atoms.
- The general formula for alkynes is CnH2n - 2.
- For hexyne: C6H(2*6) - 2 = C6H12 - 2 = C6H10.

3. **Pentene (C5H10)**:
- The prefix "pent" indicates 5 carbon atoms.
- The general formula for alkenes is CnH2n.
- For pentene: C5H(2*5) = C5H10.

4. **Acetylene (C2H2)**:
- The prefix "eth" indicates 2 carbon atoms.
- The general formula for alkynes is CnH2n - 2.
- For acetylene: C2H(2*2) - 2 = C2H4 - 2 = C2H2.

### Step 3: Match the hydrocarbons with their formulas
Now we can match the hydrocarbons from List-I with their corresponding formulas from List-II:
- **Butane (P)** matches with (2) C4H10.
- **Hexyne (Q)** matches with (1) C6H10.
- **Pentene (R)** matches with (4) C5H10.
- **Acetylene (S)** matches with (3) C2H2.

### Final Matching:
- P → 2 (Butane → C4H10)
- Q → 1 (Hexyne → C6H10)
- R → 4 (Pentene → C5H10)
- S → 3 (Acetylene → C2H2)

### Conclusion:
The correct matching is:
- PQRS = 2143