Which of the following will be the final product when `C_2H_2` reacts with HCl

Options

A. `underset(CHCl)overset(CH)(||)`
B. `underset(CHCl_2)overset(CH_3)|`
C. `undersetunderset(CHCl)overset(CHCl)(||)`
D. None of these

Explanation

To determine the final product when acetylene (C₂H₂) reacts with hydrochloric acid (HCl), we can follow these steps:

### Step 1: Identify the Reaction Type
Acetylene (C₂H₂) is an alkyne, and it undergoes electrophilic addition reactions. In this case, HCl acts as an electrophile.

**Hint:** Remember that alkynes typically react with electrophiles through addition reactions.

### Step 2: Electrophilic Addition Mechanism
In the reaction, the hydrogen atom from HCl will add to one of the carbon atoms in the triple bond of C₂H₂, while the chloride ion (Cl⁻) will add to the other carbon atom.

**Hint:** Think about how the electrophile (H⁺) and nucleophile (Cl⁻) interact with the triple bond.

### Step 3: Draw the Intermediate Product
When HCl adds to C₂H₂, it forms an intermediate product known as vinyl chloride (C₂H₃Cl). This compound has a double bond between the two carbon atoms and a chlorine atom attached to one of the carbons.

**Hint:** Visualize the structure of the intermediate product to understand where the atoms are added.

### Step 4: Final Product Formation
If the reaction conditions allow for further addition, the vinyl chloride (C₂H₃Cl) can react with another molecule of HCl. This will lead to the saturation of the double bond, resulting in the formation of 1,1-dichloroethane (C₂H₄Cl₂).

**Hint:** Consider what happens if there is excess HCl present in the reaction.

### Conclusion
The final product when C₂H₂ reacts with HCl is 1,1-dichloroethane (C₂H₄Cl₂) if the reaction goes to completion with excess HCl.

**Final Answer:** 1,1-dichloroethane (C₂H₄Cl₂)