Many years ago engineers built a canal to control water flow along a river. at the time of building the canal, the engineers did not know that they used a rock that contained iron particles. over time, the rocks have been exposed to a constant supply of water which has given the rocks an orange-brown color. it has formed a new compound called limonite. what type of weathering has occurred to these rocks?

Chemical weathering due to Oxidation occurs to these rocks.

Explanation:

The process of Chemical weathering results in changing the rocks composition resulting in the transformation of rocks because water reacts with minerals present in the rocks thereby creating various chemical reactions. It is a gradual and a continuous process because the minerals present in the rock changes according to the environment. Oxidation and hydrolysis process plays a major role in Chemical weathering.

The oxidation of (iron) and combination with oxygen and water  usually occurs and this results in the formation of hydroxides and oxides such as goethite, limonite, and hematite. This results in giving a orange -brown colors to the rocks and makes it weak. It can also be termed as 'rusting'.

it forms an anion that has a larger radius. anions have a negative charge and are larger than the original atom.