Final answer:
The false statement about carbonic acid is that it plays a minor role in the weathering of rocks. In reality, carbonic acid significantly contributes to the weathering process by helping to dissolve minerals such as limestone.
Step-by-step explanation:
The statement that is false about carbonic acid (H₂CO₃) is: 4) compared to other naturally occurring acids, carbonic acid plays a minor role in the weathering of rocks. Carbonic acid, formed when carbon dioxide dissolves in water, plays a significant role in the weathering process of rocks. It is because this acid leads to the dissolution of minerals like limestone, thus producing calcium bicarbonate, which results in many limestone features such as stalactites and stalagmites.
Carbonic acid can indeed form from the reaction of water with carbon dioxide both in the atmosphere and soil, as reflected in statements 1) and 2). The presence of carbonic acid in water increases the weathering capability of water because it helps break down rocks and minerals, as stated in 3).