The final product of the following sequence of reaction is
`CH_2=CH_2 overset(Br_2)underset(CCl_4)rarrA overset(KCN)rarrB overset(H^+/H_2O) rarrC`

Options

A.
B.
C.
D.

Answer

To determine the final product of the given sequence of reactions, let's break down each step systematically.

### Step 1: Reaction of Ethylene with Bromine
Starting with ethylene (CH₂=CH₂), we react it with bromine (Br₂) in carbon tetrachloride (CCl₄). This is an electrophilic addition reaction.

**Reaction:**
\[ \text{CH}_2=CH_2 + \text{Br}_2 \xrightarrow{\text{CCl}_4} \text{Br-CH}_2-CH_2\text{-Br} \]

**Product A:**
The product formed is 1,2-dibromoethane (Br-CH₂-CH₂-Br).

### Step 2: Reaction with Potassium Cyanide
Next, we treat the dibromoethane (Product A) with potassium cyanide (KCN). This reaction involves nucleophilic substitution where the bromine atoms are replaced by cyanide ions (CN⁻).

**Reaction:**
\[ \text{Br-CH}_2-CH_2-\text{Br} + 2 \text{KCN} \rightarrow \text{CH}_2-C(=N) \text{C} \text{(CN)}_2 \]

**Product B:**
The final product of this step is 1,2-dicyanoethane (CH₂-C(CN)₂).

### Step 3: Hydrolysis with Acid and Water
Finally, we hydrolyze the dicyano compound (Product B) using an acid (H⁺) and water (H₂O). This reaction converts the nitrile groups (CN) into carboxylic acid groups (COOH).

**Reaction:**
\[ \text{CH}_2-C(CN)_2 + 2 \text{H}_2O \xrightarrow{H^+} \text{CH}_2-C(COOH)_2 \]

**Final Product C:**
The final product is 1,2-ethanediol (HOOC-CH₂-COOH), which is a dicarboxylic acid.

### Summary of Products:
- **Product A:** 1,2-dibromoethane (Br-CH₂-CH₂-Br)
- **Product B:** 1,2-dicyanoethane (CH₂-C(CN)₂)
- **Final Product C:** 1,2-ethanediol (HOOC-CH₂-COOH)