The number of litres of air required to burn 8 litres of `C_(2)H_(4)` is approximately :-

Options

A. 40
B. 60
C. 100
D. 120

Answer

To find the number of liters of air required to burn 8 liters of ethylene (C₂H₄), we can follow these steps:

### Step 1: Write the balanced chemical equation
The combustion of ethylene (C₂H₄) in the presence of oxygen (O₂) produces carbon dioxide (CO₂) and water (H₂O). The balanced equation is:

\[ \text{C}_2\text{H}_4 + 3\text{O}_2 \rightarrow 2\text{CO}_2 + 2\text{H}_2\text{O} \]

### Step 2: Determine the moles of oxygen required
From the balanced equation, we see that 1 mole of C₂H₄ reacts with 3 moles of O₂. Therefore, to burn 8 liters of C₂H₄, we need:

\[ \text{Oxygen required} = 3 \times \text{Volume of C}_2\text{H}_4 \]

Substituting the volume of C₂H₄:

\[ \text{Oxygen required} = 3 \times 8 \text{ L} = 24 \text{ L} \]

### Step 3: Calculate the volume of air needed
Since air is composed of approximately 21% oxygen by volume, we can calculate the volume of air required to obtain the necessary oxygen.

Let \( V \) be the volume of air required. The volume of oxygen in air can be expressed as:

\[ \text{Volume of oxygen} = 0.21 \times V \]

Setting this equal to the volume of oxygen required:

\[ 0.21V = 24 \text{ L} \]

### Step 4: Solve for the volume of air
Now, we can solve for \( V \):

\[ V = \frac{24 \text{ L}}{0.21} \]

Calculating this gives:

\[ V \approx 114.29 \text{ L} \]

### Step 5: Round to the nearest whole number
Since the question asks for an approximate value, we can round this to:

\[ \text{Volume of air required} \approx 114 \text{ L} \]

### Final Answer
The number of liters of air required to burn 8 liters of C₂H₄ is approximately **114 liters**.

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