'''Acid rain''' is [[rain]] that is more [[acid]]ic than in its natural state, and is usually consider to be a pH of less than 5. (Natural rain water is slightly acidic due to the presence of dissolved [[carbon dioxide]]. Acid rain forms when [[sulfur dioxide]] dissolves in [[water]] to make [[sulfurous acid]]. The [[sulfur dioxide]] can also be oxidized to [[sulfur trioxide]] and form [[sulfuric acid]] upon reaction with [[water]] | '''Acid rain''' is [[rain]] that is more [[acid]]ic than in its natural state, and is usually consider to be a pH of less than 5. (Natural rain water is slightly acidic due to the presence of dissolved [[carbon dioxide]]. Acid rain forms when [[sulfur dioxide]] dissolves in [[water]] to make [[sulfurous acid]]. The [[sulfur dioxide]] can also be oxidized to [[sulfur trioxide]] and form [[sulfuric acid]] upon reaction with [[water]] |