Which of the following statements is not true

Options

A. HF is a stronger acid than HCl
B. Among halide ions, iodide is the most powerful reducing agent
C. Fluorine is the only halogen that does not show a variable oxidation state
D. HOCl is a stronger acid than HOBr

Explanation

To determine which statement is not true, we will analyze each statement one by one based on the information provided in the video transcript.

### Step-by-Step Solution:

1. **Statement 1: HF is a stronger acid than HCl.**
- **Analysis:** As we move down the group in the periodic table, the bond length between hydrogen and the halogen increases. This results in a weaker bond in the case of HCl compared to HF. However, HF is not a stronger acid than HCl. In fact, HCl is a stronger acid because it dissociates more completely in solution. Therefore, this statement is **not true**.

2. **Statement 2: Among halides, Iodide (I-) is the most powerful reducing agent.**
- **Analysis:** Iodide ions (I-) are indeed good reducing agents because they can easily donate electrons. The reducing ability increases down the group from fluorine to iodine. Thus, this statement is **true**.

3. **Statement 3: Fluorine is the only halogen that does not show a variable oxidation state.**
- **Analysis:** Fluorine typically exhibits only two oxidation states: -1 (in compounds like HF) and 0 (in elemental form). Other halogens like chlorine, bromine, and iodine can exhibit multiple oxidation states. Therefore, this statement is **true**.

4. **Statement 4: HOCl is a stronger acid than HOBr.**
- **Analysis:** Chlorine is more electronegative than bromine, which makes HOCl a stronger acid than HOBr. Chlorine attracts electrons more effectively, leading to a greater tendency to lose the hydrogen ion (H+). Therefore, this statement is **true**.

### Conclusion:
The statement that is **not true** is **Statement 1: HF is a stronger acid than HCl**.

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