Read the chemical equation.
[tex] 2C_2H_2 + 5O_2 \rightarrow 4CO_2 + 2H_2O [/tex]

Which of the following statements would be correct if one mole of [tex]C_2H_2[/tex] was used in this reaction?

A. One mole of oxygen was used in this reaction.
B. Five moles of oxygen were used in this reaction.
C. Four moles of carbon dioxide were produced from this reaction.
D. Two moles of carbon dioxide were produced from this reaction.



Answer :

Let's carefully analyze the balanced chemical equation:
[tex]\[ 2 \, C_2H_2 + 5 \, O_2 \rightarrow 4 \, CO_2 + 2 \, H_2O \][/tex]

To determine how many moles of each reactant and product would be involved if one mole of \(C_2H_2\) was used, we'll scale down the coefficients in the equation accordingly.

### Understanding the Coefficients
1. The equation states that 2 moles of \( C_2H_2 \) react with 5 moles of \( O_2 \) to produce 4 moles of \( CO_2 \) and 2 moles of \( H_2O \).

2. If we are using 1 mole of \( C_2H_2 \), we need to scale down everything by a factor of 2 (since the coefficient of \( C_2H_2 \) is 2).

### Adjusting for One Mole of \(C_2H_2\):
- Moles of \( O_2 \) needed:
[tex]\[ \frac{5}{2} \times 1 = 2.5 \][/tex]
So, 2.5 moles of \( O_2 \) are needed.

- Moles of \( CO_2 \) produced:
[tex]\[ \frac{4}{2} \times 1 = 2 \][/tex]
So, 2 moles of \( CO_2 \) are produced.

- Moles of \( H_2O \) produced:
[tex]\[ \frac{2}{2} \times 1 = 1 \][/tex]
So, 1 mole of \( H_2O \) is produced.

### Verifying Each Statement:
1. One mole of oxygen was used in this reaction.
- This is incorrect. From our calculation, 2.5 moles of \( O_2 \) are needed.

2. Five moles of oxygen were used in this reaction.
- This is incorrect. Only 2.5 moles of \( O_2 \) are needed.

3. Four moles of carbon dioxide were produced from this reaction.
- This is incorrect. Only 2 moles of \( CO_2 \) are produced.

4. Two moles of carbon dioxide were produced from this reaction.
- This is correct. We've determined that 2 moles of \( CO_2 \) are produced.

Thus, the correct statement is:
Two moles of carbon dioxide were produced from this reaction.