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 sequence of reactions: First, CO2 reacts with H2O to form carbonic acid (CH2O3). Then, carbonic acid dissociates into a proton (H+) and a bicarbonate ion (CHO3-).
2. Understand Le Chatelier's Principle: Adding more reactant (CO2) to the system will shift the equilibrium of the first reaction to the right, producing more carbonic acid.
3. Analyze the effect on the second reaction: As more carbonic acid is formed, it will also shift the equilibrium of the second reaction to the right, producing more H+ and bicarbonate ions.
4. Determine the effect on pH: Increasing the concentration of H+ ions in the ocean will lower the pH, making the ocean more acidic.
5. Conclude the overall impact: The additional CO2 from the underwater volcano will drive both reactions to the right, resulting in increased acidity of the ocean.

Key Concepts

Le Chatelier's Principle

Le Chatelier's Principle states that if a dynamic equilibrium is disturbed by changing the conditions, the system will adjust itself to counteract the change and restore a new equilibrium. In the context of the reaction between carbon dioxide and water, adding more CO2 will shift the equilibrium position to the right, favoring the formation of carbonic acid and subsequently increasing the concentration of protons and 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 ocean chemistry, as the increase in H+ ions lowers the pH of the water, making it more acidic. The balance between carbonic acid and its dissociation products is essential for maintaining oceanic pH levels.

Ocean Acidification

Ocean acidification refers to the decrease in pH levels of ocean water due to increased CO2 absorption from the atmosphere. When CO2 levels rise, more carbonic acid forms, leading to higher concentrations of H+ ions and lower pH. This process can have detrimental effects on marine life, particularly organisms that rely on calcium carbonate for their shells and skeletons, as increased acidity can hinder their ability to maintain these structures.