For the reation given below, identify X in the reaction
`CH_3C -= C-CH_3 overset(X)rarr CH_3COCOCH_3`

Options

A. `K_2Cr_2O_7//H_2SO_4`
B. `O_2`
C. `O_3, Zn//H_2O`
D. `HNO_3`

Answer

To identify the compound X in the reaction:

**Given Reaction:**
\[ \text{CH}_3C \equiv C\text{-CH}_3 \overset{X}{\rightarrow} \text{CH}_3COCOCH_3 \]

### Step-by-Step Solution:

1. **Identify the Reactant:**
The reactant is But-2-yne, which has the structure:
\[ \text{CH}_3C \equiv C\text{-CH}_3 \]
This is an alkyne with a triple bond between the second and third carbon atoms.

2. **Identify the Product:**
The product is:
\[ \text{CH}_3COCOCH_3 \]
This compound is a diketone, specifically 3-pentanedione.

3. **Determine the Reaction Type:**
The transformation from an alkyne to a diketone suggests that the reaction involves ozonolysis. Ozonolysis is a reaction where ozone (O₃) reacts with alkenes or alkynes to form carbonyl compounds.

4. **Write the Ozonolysis Mechanism:**
- In the first step, ozone adds to the triple bond of But-2-yne, forming an ozonide intermediate.
- In the second step, the ozonide is treated with a reducing agent (commonly zinc and water), which leads to the cleavage of the ozonide and forms the diketone.

5. **Identify the Compound X:**
From the above steps, we can conclude that the compound X is ozone (O₃) followed by a reducing agent (like zinc and water). Thus, the complete reaction can be summarized as:
\[ \text{CH}_3C \equiv C\text{-CH}_3 + O_3 \xrightarrow{Zn/H_2O} \text{CH}_3COCOCH_3 \]

### Final Answer:
The compound X is **Ozone (O₃)**.

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