Question

1. sinkholes and caves can form when limestone is dissolved. what chemical can dissolve limestone?

sulfuric acid from acid rain
citric acid from decomposing plants
nitric acid from acid rain
carbonic acid in groundwater

Explanation:

Limestone is primarily calcium carbonate ($CaCO_3$). Carbonic acid ($H_2CO_3$), formed when atmospheric carbon dioxide dissolves in groundwater ($CO_2 + H_2O
ightleftharpoons H_2CO_3$), reacts with calcium carbonate to form soluble calcium bicarbonate ($Ca(HCO_3)_2$), driving the dissolution that creates sinkholes and caves. This is the primary natural process for limestone dissolution in karst topography.

Answer:

carbonic acid in groundwater