Which of the following is false for order of `-l` effect :

Options

A. `-Fgt-Clgt-Brgt-l`
B. `-C-=CHgt-CH=CH_(2)gt-CH_(2)-CH_(3)`
C. `-C-=CNgt-underset(O)underset(||)C-OH`
D. `-Phgt-C-=CH`

Answer

To determine which statement is false regarding the order of the -I (inductive) effect, we will analyze the provided options step by step.

### Step 1: Understanding the -I Effect
The -I effect refers to the inductive effect, which is the electron-withdrawing effect of electronegative atoms or groups. The strength of the -I effect is influenced by the electronegativity of the atoms and the hybridization of the carbon atoms involved.

### Step 2: Analyzing the Options
We have four options to evaluate:

1. **Fluorine > Chlorine > Bromine > Iodine**:
- Fluorine is the most electronegative element, followed by chlorine, bromine, and iodine. This order is correct as more electronegative atoms exert a stronger -I effect.

2. **Triple Bond (sp) > Double Bond (sp2) > Single Bond (sp3)**:
- The hybridization affects the s-character. The sp hybridized carbon has 50% s-character, sp2 has 33.3%, and sp3 has 25%. More s-character means higher electronegativity and thus a stronger -I effect. This order is also correct.

3. **C≡C > C=O > C-OH**:
- In this case, the triple bond (C≡C) is more electronegative than the double bond (C=O) and the single bond (C-OH). However, the presence of oxygen in C=O and C-OH can donate electrons through resonance, which can reduce the -I effect. This statement is correct as well.

4. **Phenyl (Ph) > C≡C (triple bond)**:
- The phenyl group (Ph) is sp2 hybridized and has less s-character than the sp hybridized carbon in the triple bond. Therefore, the triple bond should exert a stronger -I effect than the phenyl group. This statement is false.

### Conclusion
The false statement regarding the order of the -I effect is:
**D: Phenyl (Ph) > C≡C (triple bond)**