When treated with ammoniacal cuprous chloride, which one among the following forms copper derivative

Options

A. `C_2H_6`
B. `C_2H_4`
C. `C_2H_2`
D. `C_6H_6`

Explanation

To solve the question, we need to determine which compound among the given options forms a copper derivative when treated with ammoniacal cuprous chloride. Here’s a step-by-step breakdown of the solution:

### Step 1: Understand the Reactants
Ammoniacal cuprous chloride is a reagent represented by NH4OH and Cu2Cl2. It is known for its ability to react with terminal alkynes to form copper derivatives.

**Hint:** Identify the components of ammoniacal cuprous chloride and their significance in the reaction.

### Step 2: Identify the Types of Hydrocarbons
The question involves identifying which of the given compounds is a terminal alkyne. Terminal alkynes are characterized by having a triple bond (C≡C) at the end of the carbon chain.

**Hint:** Recall the definitions of alkanes, alkenes, and alkynes to differentiate between them.

### Step 3: Analyze the Given Compounds
Let’s analyze the given compounds:
- C2H6: This is ethane, an alkane.
- C2H4: This is ethylene, an alkene.
- C2H2: This is acetylene, a terminal alkyne.
- C6H6: This is benzene, an aromatic compound.

**Hint:** Look for the compound that has a triple bond at the end of its carbon chain.

### Step 4: Identify the Terminal Alkyne
Among the compounds listed, C2H2 (acetylene) is the only terminal alkyne. It has the structure HC≡CH, where the triple bond is at the end of the molecule.

**Hint:** Confirm the structure of C2H2 to ensure it is a terminal alkyne.

### Step 5: Predict the Reaction
When C2H2 (acetylene) is treated with ammoniacal cuprous chloride, it reacts to form a copper derivative, resulting in a red precipitate of copper.

**Hint:** Remember that terminal alkynes react with ammoniacal cuprous chloride to produce a characteristic red precipitate.

### Conclusion
Thus, the compound that forms a copper derivative when treated with ammoniacal cuprous chloride is C2H2 (acetylene). Therefore, the correct answer is option 3.

**Final Answer:** C2H2 (acetylene) forms a copper derivative with ammoniacal cuprous chloride.