Final answer:
The correct reaction showing why the ocean is becoming more acidic is CO₂ + H₂O → H₂CO₃, which increases H⁺ in the ocean, leading to higher acidity.
Step-by-step explanation:
The reaction that correctly illustrates why the ocean is becoming more acidic is CO₂ + H₂O → H₂CO₃ (carbonic acid). When carbon dioxide (CO₂) dissolves in water (H₂O), it forms carbonic acid (H₂CO₃), which then dissociates into bicarbonate (HCO₃⁻) and hydrogen ions (H⁺). The increase in hydrogen ion concentration causes a decrease in the pH of the water, making the ocean more acidic.
The specific reaction is as follows:
Step 1: CO₂ (dissolved) + H₂O = H₂CO₃ (carbonic acid)
Step 2: H₂CO₃ ≃ H⁺ + HCO₃⁻ (bicarbonate ion)
Step 3: HCO₃⁻ → H⁺ + CO₃²⁻ (carbonate ion)