Minerals in rocks may react with the rainwater, causing the rock to be weathered. Some types of rock are easily weathered by chemicals. For example, limestone and chalk are mostly calcium carbonate. When acidic rainwater falls on limestone or chalk, a chemical reaction happens.
When the chalk (which is made of a base called calcium carbonate) is added to an acid like vinegar, a chemical reaction occurs. ... This neutralization reaction occurs naturally in the environment when weak acids in rain react with limestone and other rocks, resulting in erosion (the wearing away of rock). I hope this helps :)