Question

which set of coefficients will balance this chemical equation?
c₂h₄(g) + o₂(g) → 2co₂(g) + 2h₂o(g)
options:
1,2
1,3
2,3
2,5

Explanation:

Step1: Balance Carbon (C)

On the right, there are 2 \( \text{CO}_2 \) molecules, so 2 C atoms. On the left, \( \text{C}_2\text{H}_4 \) has 2 C atoms. So the coefficient for \( \text{C}_2\text{H}_4 \) is 1 (since 1×2 = 2 C atoms).

Step2: Balance Hydrogen (H)

On the right, \( 2\text{H}_2\text{O} \) has 2×2 = 4 H atoms. On the left, \( \text{C}_2\text{H}_4 \) has 4 H atoms (1×4). So H is balanced with \( \text{C}_2\text{H}_4 \) coefficient 1.

Step3: Balance Oxygen (O)

On the right: \( 2\text{CO}_2 \) has 2×2 = 4 O, \( 2\text{H}_2\text{O} \) has 2×1 = 2 O. Total O on right: 4 + 2 = 6. On the left, \( \text{O}_2 \) has 2 O per molecule. Let coefficient of \( \text{O}_2 \) be \( x \). Then \( 2x = 6 \) → \( x = 3 \). So coefficients are 1 (for \( \text{C}_2\text{H}_4 \)) and 3 (for \( \text{O}_2 \)).

Answer:

1, 3 (corresponding to the option "1,3")