Give the sterochemical products :
`HC-=CH + 2NaNH_2 + 2EtBr rarr (A) overset (Cs,NH_3)rarr (B) overset (Br_2)rarr (C)`.

Explanation

To solve the given question step by step, we will analyze the reactions and their stereochemical outcomes.

### Step 1: Reaction of Acetylene with Sodium Amide and Ethyl Bromide

1. **Starting Material**: Acetylene (HC≡CH).
2. **Reagents**: 2NaNH₂ and 2EtBr (C₂H₅Br).
3. **First Reaction**: Acetylene reacts with sodium amide (NaNH₂) to form a disodium acetylide.
- The reaction involves the deprotonation of acetylene by NaNH₂, resulting in the formation of sodium acetylide (Na⁺C≡C⁻).
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