Answer: The particles in a solid are packed very close to each other.
Water combines with carbon dioxide to produce slightly acidic groundwater
that dissolves limestone and forms caves.
This is because the reaction between water and carbondioxide to form
bicarbonate ions( HCO₃⁻). The bicarbonate ions dissociate into Hydrogen
atoms thereby increasing the acidity.
The acidic environment results in the formation of acidic groundwater that
dissolves limestone and forms caves.
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