List I
(A) `CH_(3) – C-=C – CH_(3)rarr` cis-2-butene (B)
`CH_(3) – C-=C – CH_(3)rarr` trans-2-butene (C)
`CH_(3)C-=C – CH_(3)rarr1`-Butyne (D) `CH_(3) – CH_(3) – C-=CH_(3)rarr2`-Butyne
List II
(1) `Na//NH_(3)(?)`
(2) `H2//Pd//BaSO_(4)`
(3) `alc. KOH, Delta`
(4) `NaNH_(2), Delta`

Options

A. `{:(,a,b,c,d),((A),2,1,3,4):}`
B. `{:(,a,b,c,d),((B),1,2,4,3):}`
C. `{:(,a,b,c,d),((C),1,2,3,4):}`
D. `{:(,a,b,c,d),((D),2,1,4,3):}`

Answer

To solve the problem of matching the reactions in List I with the appropriate reagents in List II, we will go through each reaction step by step.

### Step 1: Identify the Reaction for (A) cis-2-butene
- Starting compound: `CH3 – C≡C – CH3` (2-butyne)
- Target product: cis-2-butene
- Reagent needed: Rosenmund Catalyst (H2/Pd/BaSO4) is used to reduce alkynes to cis-alkenes.

**Conclusion for (A):** The reagent for converting 2-butyne to cis-2-butene is (2) `H2 // Pd // BaSO4`.

### Step 2: Identify the Reaction for (B) trans-2-butene
- Starting compound: `CH3 – C≡C – CH3` (2-butyne)
- Target product: trans-2-butene
- Reagent needed: Sodium in ammonia (Na/NH3) is used to reduce alkynes to trans-alkenes.

**Conclusion for (B):** The reagent for converting 2-butyne to trans-2-butene is (1) `Na // NH3`.

### Step 3: Identify the Reaction for (C) 1-Butyne
- Starting compound: `CH3C≡C – CH3` (2-butyne)
- Target product: 1-butyne
- Reagent needed: Sodium amide (NaNH2) with heat is used to deprotonate terminal alkynes and can lead to the formation of 1-butyne.

**Conclusion for (C):** The reagent for converting 2-butyne to 1-butyne is (4) `NaNH2, Δ`.

### Step 4: Identify the Reaction for (D) 2-Butyne
- Starting compound: `CH3 – CH3 – C≡C – CH3` (2-butyne)
- Target product: Internal alkyne (2-butyne)
- Reagent needed: Alcoholic potassium hydroxide (alc. KOH, Δ) is used for elimination reactions to form internal alkynes.

**Conclusion for (D):** The reagent for converting terminal alkyne to internal alkyne is (3) `alc. KOH, Δ`.

### Final Matching:
- (A) cis-2-butene → (2) `H2 // Pd // BaSO4`
- (B) trans-2-butene → (1) `Na // NH3`
- (C) 1-Butyne → (4) `NaNH2, Δ`
- (D) 2-Butyne → (3) `alc. KOH, Δ`

### Summary of Answers:
- A → 2
- B → 1
- C → 4
- D → 3