Answer: B. Because of a reaction with water, feldspar is changed into clay minerals.
Hydrolysis is simply the process whereby substances are broken down chemically by water. This depends on the solubility, oxidation, oxidation-reduction reaction, and the pH of the compound. By hydrolysis, feldspar is altered to release hydrogen. Reaction between an ion of feldspar and a molecule of water releases a solution called Kaolinite. Kaolinite is a gray or white gray clay mineral composed of aluminum silicate hydroxide.