`{:("List-I","List-II"),((P)C_(n)H_(2n+2),(1)"Alkyne"),((Q) C_(n)H_(2n),(2)"Alkene"),((R ) C_(n)H_(2n-2),(3)"Alkane"),((S)C_(n)H_(2n-1),(4)"Alkyl group"):}`

Answer

To solve the problem of matching the general formulas of hydrocarbons with their respective names, we can follow these steps:

### Step 1: Identify the General Formula for Alkanes
- The general formula for alkanes is \( C_nH_{2n+2} \).
- This means for every n carbon atoms, there are \( 2n + 2 \) hydrogen atoms.

**Hint:** Remember that alkanes are saturated hydrocarbons with single bonds.

### Step 2: Identify the General Formula for Alkenes
- The general formula for alkenes is \( C_nH_{2n} \).
- This indicates that for every n carbon atoms, there are \( 2n \) hydrogen atoms.

**Hint:** Alkenes contain at least one double bond between carbon atoms.

### Step 3: Identify the General Formula for Alkynes
- The general formula for alkynes is \( C_nH_{2n-2} \).
- This shows that for every n carbon atoms, there are \( 2n - 2 \) hydrogen atoms.

**Hint:** Alkynes contain at least one triple bond between carbon atoms.

### Step 4: Identify the General Formula for Alkyl Groups
- The general formula for alkyl groups is \( C_nH_{2n-1} \).
- This means that for every n carbon atoms, there are \( 2n - 1 \) hydrogen atoms.

**Hint:** Alkyl groups are derived from alkanes by removing one hydrogen atom.

### Step 5: Match Each Formula with Its Name
- **P: \( C_nH_{2n+2} \)** matches with **(3) Alkane**.
- **Q: \( C_nH_{2n} \)** matches with **(2) Alkene**.
- **R: \( C_nH_{2n-2} \)** matches with **(1) Alkyne**.
- **S: \( C_nH_{2n-1} \)** matches with **(4) Alkyl group**.

### Final Matching:
- P → 3 (Alkane)
- Q → 2 (Alkene)
- R → 1 (Alkyne)
- S → 4 (Alkyl group)

### Summary of Matches:
- **P (C_nH_{2n+2})** → **(3) Alkane**
- **Q (C_nH_{2n})** → **(2) Alkene**
- **R (C_nH_{2n-2})** → **(1) Alkyne**
- **S (C_nH_{2n-1})** → **(4) Alkyl group**