1.86 g of aniline completely reacts to form acetanilide. 10% of the product is lost during purification. Amount of acetanilide obtained after purification (in g) is __________` xx 10^(-2)` .

Answer

To solve the problem, we need to calculate the amount of acetanilide obtained after the reaction of aniline, accounting for the loss during purification. Here’s a step-by-step breakdown of the solution:

### Step 1: Calculate the moles of aniline
Given:
- Mass of aniline = 1.86 g
- Molar mass of aniline (C6H7N) = 93 g/mol

To find the number of moles of aniline, we use the formula:
\[ \text{Moles of aniline} = \frac{\text{Mass of aniline}}{\text{Molar mass of aniline}} = \frac{1.86 \, \text{g}}{93 \, \text{g/mol}} = 0.02 \, \text{mol} \]

### Step 2: Determine the amount of acetanilide produced
The reaction shows that 1 mole of aniline produces 1 mole of acetanilide. Therefore, the moles of acetanilide produced will also be:
\[ \text{Moles of acetanilide} = 0.02 \, \text{mol} \]

### Step 3: Calculate the mass of acetanilide
The molar mass of acetanilide (C8H9NO) is calculated as follows:
- C: 8 × 12 = 96 g
- H: 9 × 1 = 9 g
- N: 1 × 14 = 14 g
- O: 1 × 16 = 16 g

Total molar mass of acetanilide:
\[ \text{Molar mass of acetanilide} = 96 + 9 + 14 + 16 = 135 \, \text{g/mol} \]

Now, we can calculate the mass of acetanilide produced:
\[ \text{Mass of acetanilide} = \text{Moles of acetanilide} \times \text{Molar mass of acetanilide} = 0.02 \, \text{mol} \times 135 \, \text{g/mol} = 2.7 \, \text{g} \]

### Step 4: Calculate the loss during purification
We know that 10% of the product is lost during purification. Therefore, the mass lost is:
\[ \text{Mass lost} = 10\% \text{ of } 2.7 \, \text{g} = \frac{10}{100} \times 2.7 = 0.27 \, \text{g} \]

### Step 5: Calculate the final amount of acetanilide obtained
To find the final amount of acetanilide after purification, we subtract the mass lost from the initial mass:
\[ \text{Final mass of acetanilide} = 2.7 \, \text{g} - 0.27 \, \text{g} = 2.43 \, \text{g} \]

### Step 6: Express the final answer in the required format
The problem asks for the answer in the form of \(xx \times 10^{-2}\):
\[ 2.43 \, \text{g} = 243 \times 10^{-2} \, \text{g} \]

Thus, the final answer is:
\[ \text{Amount of acetanilide obtained after purification} = 243 \times 10^{-2} \, \text{g} \]

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