Which of the following is (are) correct? .

Options

A. A double bond is shorter than a single bond .
B. A sigma- vbond is weaker than a pi-bond .
C. Adouble bond is stronger than a single bond .
D. A covalent bond is stronger than a hydrogen bond .

Answer

To determine which of the statements regarding chemical bonding are correct, let's analyze each statement step by step.

### Step 1: Analyze the first statement
**Statement:** A double bond is shorter than a single bond.

**Explanation:**
- A single bond consists of one sigma bond, while a double bond consists of one sigma bond and one pi bond.
- The presence of the pi bond in a double bond allows the atoms to be pulled closer together due to increased electron density between the nuclei.
- Therefore, the bond length of a double bond is indeed shorter than that of a single bond.

**Conclusion:** This statement is **correct**.

### Step 2: Analyze the second statement
**Statement:** A sigma bond is weaker than a pi bond.

**Explanation:**
- A sigma bond is formed by the end-to-end overlap of atomic orbitals, which allows for a strong bond due to effective orbital overlap.
- A pi bond is formed by the side-to-side overlap of p-orbitals, which results in less effective overlap and thus a weaker bond.
- Therefore, sigma bonds are stronger than pi bonds.

**Conclusion:** This statement is **incorrect**.

### Step 3: Analyze the third statement
**Statement:** A double bond is stronger than a single bond.

**Explanation:**
- As previously mentioned, a double bond consists of one sigma bond and one pi bond, while a single bond consists of only one sigma bond.
- The additional pi bond in a double bond contributes to its strength, making double bonds stronger than single bonds.

**Conclusion:** This statement is **correct**.

### Step 4: Analyze the fourth statement
**Statement:** A covalent bond is stronger than a hydrogen bond.

**Explanation:**
- Covalent bonds involve the sharing of electron pairs between atoms, resulting in strong interactions.
- Hydrogen bonds are a type of dipole-dipole interaction and are generally weaker than covalent bonds.
- Therefore, covalent bonds are indeed stronger than hydrogen bonds.

**Conclusion:** This statement is **correct**.

### Final Conclusion:
The correct statements are:
- A double bond is shorter than a single bond (Correct)
- A sigma bond is weaker than a pi bond (Incorrect)
- A double bond is stronger than a single bond (Correct)
- A covalent bond is stronger than a hydrogen bond (Correct)

Thus, the correct options are A, C, and D.

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