How many coulombs are required in order to reduce 12.3 g of nitrobenzene to niline ?

Options

A. 579 C
B. 5790 c
C. 57900 C
D. 579000 C

Explanation

To determine how many coulombs are required to reduce 12.3 g of nitrobenzene (C6H5NO2) to aniline (C6H5NH2), we can follow these steps:

### Step 1: Write the balanced chemical reaction
The reduction of nitrobenzene to aniline can be represented as:
\[ \text{C}_6\text{H}_5\text{NO}_2 + 6\text{e}^- + 2\text{H}_2\text{O} \rightarrow \text{C}_6\text{H}_5\text{NH}_2 + 2\text{OH}^- \]

### Step 2: Determine the change in oxidation state
In nitrobenzene (C6H5NO2), the oxidation state of nitrogen is +5. In aniline (C6H5NH2), the oxidation state of nitrogen is -1. The change in oxidation state is:
\[ +5 \text{ to } -1 \]
This means that nitrogen gains a total of 6 electrons during the reduction process.

### Step 3: Calculate the molar mass of nitrobenzene
The molar mass of nitrobenzene (C6H5NO2) can be calculated as follows:
- Carbon (C): 12 g/mol × 6 = 72 g/mol
- Hydrogen (H): 1 g/mol × 5 = 5 g/mol
- Nitrogen (N): 14 g/mol × 1 = 14 g/mol
- Oxygen (O): 16 g/mol × 2 = 32 g/mol

Adding these together:
\[ 72 + 5 + 14 + 32 = 123 \text{ g/mol} \]

### Step 4: Calculate the number of moles of nitrobenzene
Using the formula:
\[ \text{Number of moles} = \frac{\text{mass}}{\text{molar mass}} \]
For 12.3 g of nitrobenzene:
\[ \text{Number of moles} = \frac{12.3 \text{ g}}{123 \text{ g/mol}} = 0.1 \text{ moles} \]

### Step 5: Calculate the number of electrons required
Since 1 mole of nitrobenzene requires 6 moles of electrons, for 0.1 moles:
\[ \text{Electrons required} = 0.1 \text{ moles} \times 6 \text{ electrons/mole} = 0.6 \text{ moles of electrons} \]

### Step 6: Convert moles of electrons to charge in coulombs
Using Faraday's constant (approximately 96500 C/mol):
\[ \text{Charge (C)} = \text{moles of electrons} \times \text{Faraday's constant} \]
\[ \text{Charge} = 0.6 \text{ moles} \times 96500 \text{ C/mol} = 57900 \text{ C} \]

### Final Answer
The total charge required to reduce 12.3 g of nitrobenzene to aniline is **57900 coulombs**.

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