Chapter 28, Problem 7RQ

How does rainwater become acidic? How does this affect limestone?

To determine

The cause of rainwater becoming acidic and its effect on limestone.

Answer to Problem 7RQ

Rainwater becomes acidic forming carbonic acid due the presence of carbon dioxide in the air and soil. And when this rainwater reacts with limestone, the carbonic acid partially dissolves the limestone.

Explanation of Solution

When carbon dioxide in the air and soil comes in contact of the rain water it forms carbonic acid due to which the rainwater becomes acidic. After producing carbonic acid this water percolates into the land forming groundwater. Beneath the Earth’s surface there are large deposits of limestone to store the groundwater. When the rainwater containing carbonic acid comes in contact with limestone, it partially dissolves the limestone. Thus, causing rare erosional landscapes, like sinkholes and caverns.

Conclusion:

Therefore, the rainwater becomes acidic forming carbonic acid due the presence of carbon dioxide in the air and soil. And when this rainwater reacts with limestone, the carbonic acid partially dissolves the limestone.