What is obtained, when propene is treated with N-bromo succinimide `:`

Options

A. `CH_(3) - underset( Br) underset( |) ( C ) = CH_(2)`
B. `BrCH_(2) - CH = CH_(2)`
C. `BrCH_(2) -CH = CHBr`
D. `BrCH_(2) - underset( Br) underset( |)( C ) H -CH_(2) Br`

Answer

To determine what is obtained when propene is treated with N-bromo succinimide (NBS), we can follow these steps:

### Step 1: Understand the Reactants
- **Propene (C3H6)** is an alkene with the structure CH2=CH-CH3.
- **N-bromo succinimide (NBS)** is a brominating agent that is used in allylic bromination reactions.

### Step 2: Identify the Reaction Conditions
- The reaction is typically carried out in the presence of a solvent, often carbon tetrachloride (CCl4), which helps to stabilize the reaction intermediates.

### Step 3: Mechanism of the Reaction
- The reaction mechanism involves the formation of a bromonium ion intermediate when NBS reacts with propene.
- The double bond in propene attacks the bromine atom, leading to the formation of a cyclic bromonium ion.

### Step 4: Allylic Bromination
- The bromonium ion can then be attacked by a bromide ion (which is generated from NBS) at the allylic position (the carbon adjacent to the double bond).
- In propene, the allylic hydrogen is located at the carbon that is next to the double bond (CH2-CH-CH3).

### Step 5: Product Formation
- The bromide ion will replace one of the allylic hydrogens, leading to the formation of **3-bromopropene** (C3H5Br).
- The structure of 3-bromopropene is CH2=CH-CH2Br.

### Final Answer
When propene is treated with N-bromo succinimide in the presence of CCl4, the product formed is **3-bromopropene**.

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