The least number of oxyacids are formed by:

Options

A. Chlorine
B. Fluorine
C. Sulphur
D. Nitrogen

Answer

To solve the question regarding which element forms the least number of oxyacids among Fluorine, Sulphur, and Nitrogen, we can follow these steps:

### Step 1: Understand Oxyacids
Oxyacids are acids that contain oxygen, hydrogen, and another element (the central atom). The central atom can be a non-metal, and its oxidation state can influence the number of oxyacids formed.

### Step 2: Analyze the Elements
- **Fluorine (F)**: Fluorine is highly electronegative and can only form one oxyacid, which is hypofluorous acid (HOF). This is because it cannot form multiple oxyacids due to its high electronegativity compared to oxygen.

- **Sulfur (S)**: Sulfur can form several oxyacids such as sulfurous acid (H2SO3) and sulfuric acid (H2SO4). It has multiple oxidation states (+4 and +6), allowing it to form more than one oxyacid.

- **Nitrogen (N)**: Nitrogen can also form several oxyacids, including nitrous acid (HNO2) and nitric acid (HNO3). It has different oxidation states (+3 and +5), enabling the formation of multiple oxyacids.

### Step 3: Compare the Oxyacids
From the analysis:
- **Fluorine** forms only **1 oxyacid** (HOF).
- **Sulfur** forms **2 oxyacids** (H2SO3 and H2SO4).
- **Nitrogen** forms **2 oxyacids** (HNO2 and HNO3).

### Step 4: Conclusion
Based on the number of oxyacids formed:
- The element that forms the least number of oxyacids is **Fluorine**.

### Final Answer
The least number of oxyacids are formed by **Fluorine**.

---