Complete the following by providing (A),(B), (C) and (D)
`CH_3 CH_2 CH_2 OH overset(PBr_3)to (A) overset(alc. KOH)to (B) overset(HBr)to (C ) overset(NH_3)to (D)`

Explanation

To solve the problem step by step, we will analyze each reaction in the sequence provided.

### Step 1: Reaction of n-Propanol with PBr3
- **Starting Compound**: CH₃CH₂CH₂OH (n-Propanol)
- **Reagent**: PBr₃ (Phosphorus tribromide)
- **Reaction Type**: This is an SN2 reaction where the hydroxyl group (OH) is replaced by a bromine atom (Br).
- **Mechanism**: The Br⁻ ion attacks the carbon atom bonded to the OH group, leading to the departure of the OH group as water (leaving group).
- **Product (A)**: CH₃CH₂CH₂Br (n-Bromopropane)
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