Which statement(s) is/are WRONG?

Options

A. (a) Acetylene is insoluble in conc. `H_2SO_4` due to not formation of vinyl carbocation
`(CH_2=overset(o+)CH) (HSO_4^(-))`.
B. (b) Ethylene is soluble in conc. `H_2SO_4` due to the formation of alkyne carbonation
`(H_3C-overset(o+)CH_2) (HSO_4^(-))`
C. (c) But-2-yne dissolves in conc. `H_2SO_4` due to the formation of vinyl carbocation `(Me-overset(o+)C=CH-Me)(HSO_4^(-))`, but it is stabilised by electron-donating methyl group and is more stable than the vinyl carbocation formed from acetylene.
D. (d) More the s character in the positively charged C, the more stable is the carbocation and more likely is its formation.

Answer

To determine which statement(s) is/are wrong regarding the properties of alkynes and their behavior in concentrated sulfuric acid (H2SO4), we will analyze each statement step by step.

### Step-by-Step Solution:

1. **Statement Analysis**:
- **Statement 1**: "C2H2 (acetylene) is insoluble in concentrated H2SO4 due to the formation of vinyl carbonate."
- **Analysis**: This statement is correct. Acetylene does not dissolve in concentrated sulfuric acid because the proposed vinyl carbonate is unstable. Therefore, acetylene remains insoluble.

2. **Statement 2**: "Ethylene is soluble in concentrated H2SO4 due to the formation of alkyne."
- **Analysis**: This statement is also correct. Ethylene (C2H4) reacts with concentrated sulfuric acid to form an alkyl hydrogen sulfate, which is a stable intermediate. Hence, ethylene is soluble in concentrated H2SO4.

3. **Statement 3**: "But-2-yne dissolved in concentrated H2SO4 due to the formation of vinyl carbocation which is stabilized by the electron donating methyl group and is more stable than a vinyl carbocation."
- **Analysis**: This statement is correct. But-2-yne can form a vinyl carbocation, which is stabilized by the adjacent electron-donating methyl group, making it more stable than a simple vinyl carbocation.

4. **Statement 4**: "More the s-character in the positively charged carbon, the more stable is the carbocation and more likely is its formation."
- **Analysis**: This statement is wrong. As the s-character increases, the electronegativity of the carbon atom also increases, which makes the carbocation less stable. Therefore, the formation of carbocations becomes less favorable with increased s-character.

### Conclusion:
Based on the analysis, the only incorrect statement is **Statement 4**.

### Final Answer:
The wrong statement is **Statement 4**.

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