The composition of a sample of formula `Ni_(0.98)O_(1.00)` percentage of nickel present in the form of Ni(III) is nearly

Options

A. 96
B. 4
C. 7
D. 93

Explanation

To find the percentage of nickel present in the form of Ni(III) in the compound Ni₀.98O₁.00, we can follow these steps:

### Step 1: Define Variables
Let:
- \( x \) = amount of Ni(III) present
- Therefore, the amount of Ni(II) present will be \( 0.98 - x \)

### Step 2: Write the Charge Balance Equation
The overall charge of the compound must be neutral. Nickel can exist in two oxidation states here: Ni(II) and Ni(III). The charge balance can be expressed as:
- The charge from Ni(III) is \( 3x \) (since each Ni(III) contributes +3)
- The charge from Ni(II) is \( 2(0.98 - x) \) (since each Ni(II) contributes +2)

The charge from oxygen (O) is -2 (since there is one O atom).

Thus, the charge balance equation can be set up as:
\[ 3x + 2(0.98 - x) = 2 \]

### Step 3: Solve the Equation
Now, we can simplify and solve for \( x \):
1. Expand the equation:
\[ 3x + 1.96 - 2x = 2 \]
2. Combine like terms:
\[ x + 1.96 = 2 \]
3. Isolate \( x \):
\[ x = 2 - 1.96 \]
\[ x = 0.04 \]

This means there are 0.04 moles of Ni(III) in the compound.

### Step 4: Calculate the Total Amount of Nickel
The total amount of nickel in the compound is given by the formula:
- Total Ni = \( 0.98 \) moles

### Step 5: Calculate the Percentage of Ni(III)
To find the percentage of nickel in the form of Ni(III):
1. Use the formula for percentage:
\[ \text{Percentage of Ni(III)} = \left( \frac{\text{Amount of Ni(III)}}{\text{Total Ni}} \right) \times 100 \]
2. Substitute the values:
\[ \text{Percentage of Ni(III)} = \left( \frac{0.04}{0.98} \right) \times 100 \]
\[ \text{Percentage of Ni(III)} \approx 4.08\% \]

### Conclusion
The percentage of nickel present in the form of Ni(III) is approximately **4.08%**.

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