What are the possible intermediates in the following reaction?

${\mathrm{CH}}_3{\mathrm{CH}}_2\mathrm{CH}={\mathrm{CH}}_2\frac{\left(1\right){\mathrm{Br}}_2+{\mathrm{CCl}}_4}{\left(2\right){\mathrm{NaNH}}_2; \mathrm{\Delta }}⟶{\mathrm{CH}}_3{\mathrm{CH}}_2\mathrm{C}\equiv \mathrm{CH}$

Reaction Intermediates: Alkene to Alkyne Conversion

The conversion of CH₃CH₂CH=CH₂ to CH₃CH₂C≡CH involves the following steps:

Step 1: Bromination

CH₃CH₂CH=CH₂ + Br₂→ CH₃CH₂CHBr-CH₂Br 
(in CCl₄ solvent)

Key Intermediate:

1,2-Dibromobutane (vicinal dibromide)
Structure: CH₃CH₂CHBr-CH₂Br

This intermediate is formed by the addition of bromine across the C=C double bond, creating two adjacent carbon atoms each bearing a bromine atom.

Step 2: Double Dehydrohalogenation

CH₃CH₂CHBr-CH₂Br + 2 NaNH₂→ CH₃CH₂C≡CH + 2 NaBr + 2 NH₃
(with heat, Δ)

Mechanism Summary:

1. Bromination: Br₂ adds across the double bond to form a vicinal dibromide intermediate
2. First elimination: NaNH₂ removes HBr to form an alkene
3. Second elimination: NaNH₂ removes another HBr to form the alkyne

Final Product: 1-butyne (CH₃CH₂C≡CH)