the ion which is commonly found free in the cell is

Options

A. potassium
B. borate
C. sulphur
D. nitrogen

Answer

To answer the question "the ion which is commonly found free in the cell is," we will analyze the options provided and identify the correct answer through a step-by-step approach.

### Step 1: Understand the Question
The question asks for the ion that is commonly found free in the cell. This implies that we need to identify an ion that exists in its ionic form and is prevalent within cellular environments.

### Step 2: Analyze the Options
We have four options to consider:
- Option A: Potassium (K⁺)
- Option B: Borate (B(OH)₄⁻)
- Option C: Sulfur (S²⁻)
- Option D: Nitrogen (N³⁻)

### Step 3: Evaluate Each Option
1. **Potassium (K⁺)**:
- Potassium is known to be the main intracellular ion in cells. It exists in the form of K⁺ and plays a crucial role in maintaining fluid and electrolyte balance within the cell.

2. **Borate (B(OH)₄⁻)**:
- Borate is not commonly found free in cells and is not a major intracellular ion.

3. **Sulfur (S²⁻)**:
- Sulfur is typically found in organic compounds and is not commonly present as a free ion in cells.

4. **Nitrogen (N³⁻)**:
- Nitrogen is usually found in the form of organic compounds such as amino acids and nucleotides, rather than as a free ion.

### Step 4: Identify the Correct Answer
Based on the analysis, Potassium (K⁺) is the only ion that is commonly found free in the cell. It is essential for various cellular functions and is absorbed in the form of K⁺.

### Conclusion
The correct answer to the question is **Option A: Potassium**.

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