Which of the following has maximum covalent radius?

Options

A. C-C
B. C=C
C. `C-=C`
D. all of these

Answer

To determine which of the given options has the maximum covalent radius, we need to understand the concept of covalent radius and how it relates to bond types.

### Step-by-Step Solution:

1. **Understanding Covalent Radius**:
- The covalent radius is defined as half the distance between the nuclei of two atoms bonded together in a molecule. It reflects how far the outermost electrons of an atom extend into space when it forms a covalent bond.

2. **Bond Types and Their Influence on Covalent Radius**:
- Covalent bonds can be single, double, or triple. The bond order affects the bond length:
- **Single Bond (e.g., C-C)**: The atoms are bonded by one pair of electrons. This bond has the longest bond length and thus the largest covalent radius.
- **Double Bond (e.g., C=C)**: The atoms are bonded by two pairs of electrons. This bond is shorter than a single bond, resulting in a smaller covalent radius.
- **Triple Bond (e.g., C≡C)**: The atoms are bonded by three pairs of electrons. This bond has the shortest bond length and the smallest covalent radius.

3. **Comparing Covalent Radii**:
- Since the covalent radius decreases as the bond order increases (from single to double to triple), the maximum covalent radius will be associated with a single bond.

4. **Conclusion**:
- Therefore, the option that represents a single bond will have the maximum covalent radius.

### Final Answer:
The option with the single bond will have the maximum covalent radius.

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