Question

Limestone is a naturally occurring mineral rich in calcium carbonate (CaCO₃). In water, calcium carbonate dissolves to form carbonate (CO₃²⁻), a weak base that acts as a buffer. Which would you expect to be more affected by acid rain, an environment rich in limestone or an environment poor in limestone?

a) the prescience of limestone would not make a difference.
b) an environment rich in limestone would be more affected by acid rain.
c) an environment poor in limestone would be more affected by acid rain.
d) the impact would depend on the type of vegetation present.

Answer 1

An environment poor in limestone would be more affected by acid rain as it lacks the buffering capacity provided by limestone's chemical reaction with sulfuric acid. The correct option is c.

Step-by-step explanation:

When considering the effects of acid rain on different environments, limestone plays a pivotal role due to its chemical properties. Limestone, being predominantly composed of calcium carbonate (CaCO₃), reacts with the sulfuric acid found in acid rain according to the following reaction: CaCO₃(s) + H₂SO₄ (aq) → CaSO₄(s) + H₂O(1) + CO₂(g). This reaction leads to the dissolution of limestone, releasing water and carbon dioxide.

In essence, an environment rich in limestone would serve as a buffer, reducing the acidity of rainwater through this chemical reaction. Conversely, an environment poor in limestone would lack this buffering capacity, making it more susceptible to the corrosive effects of acid precipitation. Therefore, the correct answer is option c: an environment poor in limestone would be more affected by acid rain.