What is the product when acetylene reacts with HOCl

Options

A. `CH_3COCl`
B. `ClCHCOOH`
C. `Cl_2CHCHO`
D. `ClCH_2CHO`

Answer

To determine the product when acetylene (ethyne, CH≡CH) reacts with hypochlorous acid (HOCl), we can follow these steps:

### Step 1: Understand the Reactants
Acetylene (C2H2) is a simple alkyne with a triple bond between two carbon atoms. Hypochlorous acid (HOCl) is a weak acid that can act as both a source of chlorine (Cl) and hydroxyl (OH) groups.

### Step 2: Initial Reaction
When acetylene reacts with HOCl, the first step involves the addition of HOCl across the triple bond of acetylene. The triple bond will break, and the Cl and OH groups will add to the carbon atoms.

The reaction can be represented as follows:
\[ \text{CH} \equiv \text{CH} + \text{HOCl} \rightarrow \text{Cl-CH}=\text{CH-OH} \]

### Step 3: Formation of Dihalocarbonyl Compound
In the first step, we form a compound with a double bond between the two carbon atoms and the addition of Cl and OH groups, resulting in 2-chloroethanol (Cl-CH=CH-OH).

### Step 4: Second Addition of HOCl
In the next stage, another molecule of HOCl will react with the product formed in the first step. The Cl and OH groups will again add to the carbon atoms.

The reaction can be represented as follows:
\[ \text{Cl-CH}=\text{CH-OH} + \text{HOCl} \rightarrow \text{Cl-CH}(\text{Cl})-\text{CH}(\text{OH}) \]

### Step 5: Final Product Formation
After the second addition, we have a compound with two Cl atoms and one OH group. The final product can be represented as:
\[ \text{Cl-CH}(\text{Cl})-\text{CH}(\text{OH}) \]

### Step 6: Elimination of Water
In the final step, water is removed from the compound, leading to the formation of the final product, which is 2,2-dichloroethanol.

### Final Answer
The final product when acetylene reacts with HOCl is **2,2-Dichloroethanol**.

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