C—X bond is strongest in

Options

A. `CH_(3)Cl`
B. `CH_(3)Br`
C. `CH_(3)F`
D. `CH_(3)I`

Answer

To determine which C—X bond is the strongest among the options given (where X can be Fluorine (F), Chlorine (Cl), Bromine (Br), or Iodine (I)), we need to analyze the bond lengths and the extent of orbital overlap for each bond.

### Step 1: Understanding C—X Bonds
The C—X bond refers to the bond between carbon (C) and a halogen (X). The halogens in question are fluorine (F), chlorine (Cl), bromine (Br), and iodine (I).

### Step 2: Analyzing Bond Lengths
The strength of a bond is inversely related to its bond length. The shorter the bond length, the stronger the bond. Generally, the bond lengths for C—X bonds increase as we move down the group in the periodic table:
- C—F bond is the shortest.
- C—Cl bond is longer than C—F.
- C—Br bond is longer than C—Cl.
- C—I bond is the longest.

### Step 3: Comparing Overlap
The strength of the bond also depends on the extent of orbital overlap:
- The overlap between 2p (from carbon) and 2p (from fluorine) is the greatest, leading to a stronger bond.
- The overlap between 2p (from carbon) and 3p (from chlorine) is less than that of C—F.
- The overlap between 2p (from carbon) and 4p (from bromine) is even less.
- The overlap between 2p (from carbon) and 5p (from iodine) is the least.

### Step 4: Conclusion
Based on the bond lengths and the extent of overlap, we can conclude:
- The C—F bond is the strongest due to its short bond length and significant overlap.

### Final Answer
The C—X bond is strongest in **C—F** (Carbon-Fluorine bond).

---