Choose the correct set of reagents for the following conversion. trans `(Ph-CH=CH=CH-CH_(3))rarr cis(Ph-CH=CH-CH_(3))`

Options

A. `Br_(2),alc odot KOH,NaNH_(2)Na(LiqNH_(3))`
B. `Br_(2),alc odot KOH,NaNH_(2),H_(2)` Lindlar Catayst `
C. `Br_(2),alc odot KOH,NaNH_(2),H_(2)` Lindlar Catayst
D. `Br_(2),aq odot KOH,NaNH_(2),Na(LiqNH_(3))`

Answer

To convert trans-Ph-CH=CH-CH3 to cis-Ph-CH=CH-CH3, we can follow these steps:

### Step 1: Identify the Reaction Type
The conversion from trans to cis is a geometric isomerization. This can typically be achieved through catalytic hydrogenation.

### Step 2: Choose the Reagents
For this conversion, we will use hydrogen gas (H2) in the presence of a catalyst. A common catalyst for this type of reaction is Lindlar's catalyst, which selectively hydrogenates alkynes to cis-alkenes without further reducing them to alkanes.

### Step 3: Perform the Reaction
1. **Add H2 in the presence of Lindlar's catalyst**: This will facilitate the hydrogenation of the double bond in the trans isomer, leading to the formation of the cis isomer.

### Step 4: Write the Final Product
After the reaction, the product will be cis-Ph-CH=CH-CH3.

### Summary of the Reaction
- Starting Material: trans-Ph-CH=CH-CH3
- Reagents: H2, Lindlar's catalyst
- Product: cis-Ph-CH=CH-CH3