Consider the reaction between carbon dioxide and water to form carbonic acid:CO2(g)+H2O(l)⇌CH2O3(aq)In the ocean, carbonic acid immediately dissociates to form a proton and bicarbonate ion, as follows:CH2O3(aq)+H+(aq)⇌CHO3−(aq)If an underwater volcano bubbled additional CO2 into the ocean, would this sequence of reactions be driven to the left or the right? How would this affect the pH of the ocean?

Verified step by step guidance

1. Identify the initial reaction: CO2(g) + H2O(l) ⇌ CH2O3(aq).
2. Recognize that the addition of CO2 from the volcano increases the concentration of CO2 in the system.
3. Apply Le Chatelier's Principle, which states that if a dynamic equilibrium is disturbed by changing the conditions, the position of equilibrium shifts to counteract the change.
4. Determine that the increase in CO2 will shift the equilibrium to the right, favoring the formation of more carbonic acid (CH2O3).
5. Understand that as more carbonic acid forms, it dissociates into H+ and CHO3−, increasing the concentration of H+ ions and thus lowering the pH of the ocean, making it more acidic.

Key Concepts

Le Chatelier's Principle

Le Chatelier's Principle states that if a dynamic equilibrium is disturbed by changing the conditions, the position of equilibrium shifts to counteract the change. In the context of the reaction between carbon dioxide and water, adding more CO2 will shift the equilibrium to the right, favoring the formation of carbonic acid and subsequently bicarbonate ions.

Dissociation of Carbonic Acid

Carbonic acid (H2CO3) dissociates in water to produce hydrogen ions (H+) and bicarbonate ions (HCO3−). This dissociation is crucial for understanding how increased CO2 levels affect ocean chemistry. The release of H+ ions contributes to a decrease in pH, making the ocean more acidic.

pH and Ocean Acidification

pH is a measure of the acidity or basicity of a solution, with lower values indicating higher acidity. When CO2 levels rise in the ocean, the increased formation of carbonic acid leads to more H+ ions, thus lowering the pH. This phenomenon, known as ocean acidification, can have detrimental effects on marine life, particularly organisms that rely on calcium carbonate for their shells and skeletons.