The number of litres of air required to burn 8litres of `C_(2)H_(2)` is approximately (air contains `20% " of "O_(2)`)

Options

A. 40
B. 60
C. 80
D. 100

Explanation

To solve the problem of how many litres of air are required to burn 8 litres of \(C_2H_2\) (acetylene), we can follow these steps:

### Step 1: Write the balanced chemical equation for the combustion of acetylene.
The combustion of acetylene can be represented by the following balanced equation:

\[ C_2H_2 + \frac{5}{2} O_2 \rightarrow 2 CO_2 + H_2O \]

### Step 2: Determine the amount of \(O_2\) needed to burn 8 litres of \(C_2H_2\).
From the balanced equation, we see that 1 litre of \(C_2H_2\) requires \(\frac{5}{2}\) litres of \(O_2\). Therefore, for 8 litres of \(C_2H_2\):

\[ \text{O}_2 \text{ required} = 8 \, \text{litres} \times \frac{5}{2} = 20 \, \text{litres} \]

### Step 3: Calculate the volume of air needed to supply the required \(O_2\).
Since air contains 20% \(O_2\), we can set up the following equation to find the volume of air (\(x\)) needed to provide 20 litres of \(O_2\):

\[ \frac{20}{100} \times x = 20 \]

### Step 4: Solve for \(x\).
To find \(x\), we rearrange the equation:

\[ x = \frac{20 \times 100}{20} = 100 \, \text{litres} \]

### Conclusion:
The number of litres of air required to burn 8 litres of \(C_2H_2\) is approximately **100 litres**.

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