Assertion : Acetylene is more acidic than ethylene.
Reason : Acetylene has sp character of carbon and, therefore, more s-character.

Options

A. Assertion and reason both are correct statements and reason is correct explanation for assertion.
B. Assertion and reason both are correct statements but reason is not correct explanation for assertion
C. Assertion is correct statement but reason is wrong statement
D. Assertion is wrong statement but reason is correct statement

Answer

To determine whether the assertion "Acetylene is more acidic than ethylene" is true and whether the reason "Acetylene has sp character of carbon and, therefore, more s-character" is valid, we can follow these steps:

### Step 1: Understand the Structures of Acetylene and Ethylene
- **Acetylene (C₂H₂)** has a triple bond between the two carbon atoms, represented as H-C≡C-H.
- **Ethylene (C₂H₄)** has a double bond between the two carbon atoms, represented as H₂C=CH₂.

### Step 2: Identify the Hybridization of Carbon Atoms
- In **acetylene**, the carbon atoms are sp hybridized because they form a triple bond (one sigma bond and two pi bonds). The hybridization can be determined as follows:
- Number of sigma bonds = 1 (from the triple bond) + 1 (from the hydrogen) = 2
- Therefore, the hybridization is sp (2 regions of electron density).

- In **ethylene**, the carbon atoms are sp² hybridized because they form a double bond (one sigma bond and one pi bond). The hybridization can be determined as follows:
- Number of sigma bonds = 1 (from the double bond) + 2 (from the two hydrogens) = 3
- Therefore, the hybridization is sp² (3 regions of electron density).

### Step 3: Analyze the Acidity of Acetylene and Ethylene
- Acidity is related to the stability of the conjugate base formed after the acid donates a proton (H⁺).
- When acetylene donates a proton, it forms the acetylide ion (C≡C⁻). The negative charge on the carbon in the acetylide ion is stabilized by the sp hybridization, which has 50% s-character.

- When ethylene donates a proton, it forms the vinyl anion (C=CH₂⁻). The negative charge on the carbon in the vinyl anion is less stable because it is sp² hybridized, which has 33% s-character.

### Step 4: Compare the Stability of the Conjugate Bases
- The greater the s-character, the closer the negative charge is to the nucleus, leading to greater stability of the conjugate base.
- Since the acetylide ion (from acetylene) has 50% s-character and the vinyl anion (from ethylene) has 33% s-character, the acetylide ion is more stable than the vinyl anion.

### Conclusion
- Therefore, acetylene is indeed more acidic than ethylene because its conjugate base (acetylide ion) is more stable due to higher s-character.

### Final Answer
- **Assertion**: True (Acetylene is more acidic than ethylene).
- **Reason**: True (Acetylene has sp character of carbon and, therefore, more s-character).