Molybdenum is available in which ionic form?

Options

A. `Mo^(3+)`
B. `Mo^(4+)`
C. `MoO_(2)^(2-)`
D. Both (1) and (2)

Answer

To determine the ionic form in which molybdenum is available, we can follow these steps:

### Step 1: Understand the Role of Molybdenum
Molybdenum is a micronutrient essential for plants, particularly in nitrogen fixation. It is a part of important enzymes like nitrogenase and nitrate reductase.

**Hint:** Molybdenum is crucial for nitrogen metabolism in plants.

### Step 2: Identify the Ionic Forms of Molybdenum
The question presents four options regarding the ionic forms of molybdenum:
1. Mo^+3
2. Mo^+4
3. MoO_2^2-
4. Both 1 and 2

**Hint:** Look for the correct oxidation states of molybdenum that are relevant in plant nutrition.

### Step 3: Recognize the Form in Which Molybdenum is Absorbed
When plants absorb molybdenum from the soil, it is typically in the form of molybdate, which is represented as MoO_2^2-. This indicates that the molybdenum is in the +6 oxidation state.

**Hint:** Molybdenum is usually absorbed as a molybdate ion.

### Step 4: Analyze the Options
- Mo^+3 and Mo^+4 are not the forms in which molybdenum is primarily available to plants.
- MoO_2^2- is the correct form, as it represents the molybdate ion.

**Hint:** Focus on the chemical formula that indicates the presence of oxygen with molybdenum.

### Step 5: Conclusion
Based on the analysis, the correct ionic form in which molybdenum is available is MoO_2^2-.

**Final Answer:** Molybdenum is available in the ionic form MoO_2^2-.