Which option is not matched in correct sequence

Options

A. `d^(5), d^(3), d^(1), d^(4) rarr" increasing magnetic moment"`
B. `Mo, M_(2)O_(3), MO_(2), M_(2)O_(5)rarr" decreasing basic strength"`
C. `Sc, V, Cr, Mn rarr" increasing number of oxidation state"`
D. `Co^(2+), Fe^(+3), Cr^(+3), Sc^(+3)rarr" increasing stability"`

Answer

To determine which option is not matched in the correct sequence, we will analyze each option provided in the question step by step.

### Step 1: Analyze Option 1 (D5, D3, D1, D4 - Increasing Magnetic Moment)
1. **Magnetic Moment Formula**: The magnetic moment (μ) is given by the formula:
\[ μ = \sqrt{n(n + 2)} \]
where \( n \) is the number of unpaired electrons.

2. **Determine Unpaired Electrons**:
- For D1: 1 unpaired electron
- For D3: 3 unpaired electrons
- For D4: 4 unpaired electrons
- For D5: 5 unpaired electrons

3. **Calculate Magnetic Moments**:
- For D1: \( μ = \sqrt{1(1 + 2)} = \sqrt{3} \approx 1.73 \)
- For D3: \( μ = \sqrt{3(3 + 2)} = \sqrt{15} \approx 3.87 \)
- For D4: \( μ = \sqrt{4(4 + 2)} = \sqrt{24} \approx 4.90 \)
- For D5: \( μ = \sqrt{5(5 + 2)} = \sqrt{35} \approx 5.92 \)

4. **Order of Magnetic Moments**: The increasing order of magnetic moments should be:
- D1 < D3 < D4 < D5

5. **Conclusion for Option 1**: The sequence D5, D3, D1, D4 is incorrect. The correct order is D1, D3, D4, D5.

### Step 2: Analyze Option 2 (Mo, M2O3, Mo2, M2O5 - Decreasing Basic Strength)
1. **Oxidation States**:
- Mo: 0
- M2O3: +3 (Mo is +3 due to 3 oxygen at -2)
- M2O4: +4
- M2O5: +5

2. **Basic vs Acidic Strength**: As oxidation state increases, basic strength decreases and acidic strength increases.

3. **Conclusion for Option 2**: The order is correct as stated.

### Step 3: Analyze Option 3 (Scandium, Vanadium, Chromium, Manganese - Increasing Oxidation State)
1. **Oxidation States**:
- Scandium: +2, +3
- Vanadium: +2, +3, +4, +5
- Chromium: +2, +3, +6
- Manganese: +2, +4, +7

2. **Increasing Order**: The sequence of increasing oxidation states is correct.

3. **Conclusion for Option 3**: The order is correct.

### Step 4: Analyze Option 4 (Cobalt +2, Iron +3, Chromium +3, Scandium +3 - Increasing Stability)
1. **Stability and Inert Gas Configuration**:
- Cobalt +2: 3d7
- Iron +3: 3d5
- Chromium +3: 3d3
- Scandium +3: 3d1

2. **Stability Order**: The stability increases as they approach the inert gas configuration.

3. **Conclusion for Option 4**: The order is correct.

### Final Conclusion
The option that is not matched in the correct sequence is **Option 1** (D5, D3, D1, D4 - Increasing Magnetic Moment).