Which coefficient should be placed in front of O_2(g) to correctly balance the following chemical equation?O_2(g) + 2H_2O(l) + 4Ag(s) → 4OH^-(aq) + 4Ag^+(aq)

• A. 2
• B. 1
• C. 0.5
• D. 4

Answer: (B)

Verified step by step guidance

1. Identify the elements involved in the reaction and write down the number of atoms of each element on both sides of the equation. The elements here are oxygen (O), hydrogen (H), and silver (Ag).
2. Count the atoms of each element on the product side: For oxygen, there are 4 OH⁻ ions, each containing 1 oxygen atom, so total oxygen atoms = 4; for hydrogen, 4 OH⁻ ions each have 1 hydrogen atom, so total hydrogen atoms = 4; for silver, there are 4 Ag⁺ ions, so total silver atoms = 4.
3. Count the atoms on the reactant side: Water (H₂O) has 2 hydrogen atoms and 1 oxygen atom per molecule, and silver (Ag) is elemental. The coefficient in front of H₂O is 2, so total hydrogen atoms = 2 × 2 = 4, and total oxygen atoms = 2 × 1 = 2. Silver atoms are 4 from the coefficient in front of Ag.
4. To balance oxygen atoms, adjust the coefficient in front of O₂. Since O₂ has 2 oxygen atoms per molecule, set the coefficient as x and write the oxygen balance equation: 2 (from H₂O) + 2x (from O₂) = 4 (from OH⁻). Solve for x to find the coefficient for O₂.
5. Verify that all elements are balanced with the chosen coefficient for O₂, ensuring the number of atoms of each element is equal on both sides of the equation.