`2HC-=CHoverset(CH_2Cl_2)underset(+NH_4Cl)rarr(A)overset(1 mol)underset(HCl)rarr(B)`
Compounds (A) and (B) are:

Options

A.
B.
C.
D.

Explanation

To solve the question, we will analyze the reactions step by step.

### Step 1: Identify the starting materials
We start with two moles of acetylene (C2H2), which has the structure H-C≡C-H.

### Step 2: Reaction with CH2Cl2 and NH4Cl
When acetylene reacts with CH2Cl2 (dichloromethane) in the presence of NH4Cl, it undergoes a reaction to form vinyl acetylene. The reaction can be represented as follows:

\[ 2 \text{C}_2\text{H}_2 + \text{CH}_2\text{Cl}_2 + \text{NH}_4\text{Cl} \rightarrow \text{A (Vinyl Acetylene)} \]

The structure of vinyl acetylene is H2C=CH-C≡C-H, which has a double bond between the first two carbon atoms and a triple bond between the last two carbon atoms.

### Step 3: Formation of Compound A
Thus, compound A is vinyl acetylene (H2C=CH-C≡C-H).

### Step 4: Reaction of Compound A with HCl
Next, compound A (vinyl acetylene) reacts with one mole of HCl. This reaction is an electrophilic addition where HCl adds across the double bond of vinyl acetylene. The reaction can be represented as follows:

\[ \text{A (Vinyl Acetylene)} + \text{HCl} \rightarrow \text{B (Conjugated Diene)} \]

### Step 5: Formation of Compound B
The addition of HCl leads to the formation of a stable conjugated diene. The structure of compound B will be H2C=CH-CH=CH2 (butadiene).

### Summary of Compounds
- Compound A: Vinyl Acetylene (H2C=CH-C≡C-H)
- Compound B: Butadiene (H2C=CH-CH=CH2)

### Final Answer
Thus, the compounds A and B are:
- A: Vinyl Acetylene
- B: Butadiene

---