Which of the following reagents on reaction with acetylene yeild same product?

Options

A. `O_(3)//H_(2)O+H^(+)`
B. `KMnO_(4)//OH^(-)//H_(2)O` (cold)
C. `SeO_(2)`
D. `O_(3)+Zn+H_(2)O`

Answer

To determine which reagents yield the same product when reacted with acetylene (C2H2), we will analyze the reactions step by step.

### Step 1: Identify the structure of acetylene
Acetylene is represented as:
\[ \text{C} \equiv \text{C} \]
This means it has a triple bond between two carbon atoms.

**Hint:** Remember that acetylene is the simplest alkyne with the formula C2H2.

### Step 2: Reaction with Ozone (O3)
When acetylene reacts with ozone, the triple bond breaks, and it forms an ozonide intermediate:
\[ \text{C} \equiv \text{C} + \text{O}_3 \rightarrow \text{C} \text{C} \text{O}_3 \]
Upon acid hydrolysis, this ozonide will yield:
\[ \text{HC} = \text{C}(\text{OH}) + \text{HC} = \text{C}(\text{OH}) \]
This results in the formation of two molecules of acetic acid (carboxylic acid).

**Hint:** Ozonolysis typically leads to the formation of carbonyl compounds or carboxylic acids.

### Step 3: Reaction with Alkaline KMnO4
When acetylene reacts with alkaline potassium permanganate (KMnO4) in cold water, it undergoes oxidative cleavage:
\[ \text{C} \equiv \text{C} + \text{KMnO}_4 \rightarrow \text{C} = \text{C}(\text{OH}) + \text{C} = \text{C}(\text{OH}) \]
This results in the formation of glyoxal (C2H2O2).

**Hint:** Alkaline KMnO4 is a strong oxidizing agent that can cleave double and triple bonds.

### Step 4: Reaction with Selenium Oxide (SeO2)
Selenium oxide is typically used for allylic oxidation and does not react with acetylene:
\[ \text{C} \equiv \text{C} + \text{SeO}_2 \rightarrow \text{No Reaction} \]

**Hint:** Some reagents are selective and may not react with certain types of hydrocarbons.

### Step 5: Reaction with Ozone followed by Zinc and Water
Similar to the first reaction with ozone, when acetylene reacts with ozone and is then treated with zinc in water, it also leads to the formation of glyoxal:
\[ \text{C} \equiv \text{C} + \text{O}_3 \rightarrow \text{C} = \text{C}(\text{OH}) + \text{C} = \text{C}(\text{OH}) \]
This results in glyoxal as well.

**Hint:** Reduction with zinc after ozonolysis can help convert ozonides into carbonyl compounds.

### Conclusion
From the analysis:
- The reaction with ozone yields carboxylic acids.
- The reaction with alkaline KMnO4 yields glyoxal.
- Selenium oxide shows no reaction.
- The reaction with ozone followed by zinc yields glyoxal.

Thus, the reagents that yield the same product (glyoxal) when reacted with acetylene are:
- Alkaline KMnO4
- Ozone followed by zinc and water

**Final Answer:** The correct options are 2 (KMnO4) and 4 (Ozone followed by zinc and water).