To effectively neutralize the pH levels of lakes and rivers impacted by acid rain, chemical methods can be employed to counteract the acidity. One common method is the addition of alkaline substances, which can help to raise the pH and restore the balance in the water. Some of the most commonly used substances for this purpose are:1. Limestone Calcium carbonate, CaCO3 : Limestone is a natural and abundant source of calcium carbonate. When added to lakes or rivers, it reacts with the acidic water to form calcium sulfate and carbon dioxide, which helps to raise the pH level. The reaction is as follows:CaCO3 + H2SO4 CaSO4 + CO2 + H2O2. Lime Calcium hydroxide, Ca OH 2 : Lime can be added to the water to neutralize the acidity. It reacts with the acidic components in the water, such as sulfuric acid, to form calcium sulfate and water. The reaction is as follows:Ca OH 2 + H2SO4 CaSO4 + 2H2O3. Sodium bicarbonate NaHCO3 : Sodium bicarbonate, also known as baking soda, can be used to neutralize acidic water. When added to the water, it reacts with the acidic components to form sodium sulfate, carbon dioxide, and water. The reaction is as follows:2NaHCO3 + H2SO4 Na2SO4 + 2CO2 + 2H2O4. Soda ash Sodium carbonate, Na2CO3 : Soda ash can be added to the water to neutralize the acidity. It reacts with the acidic components in the water, such as sulfuric acid, to form sodium sulfate and carbon dioxide. The reaction is as follows:Na2CO3 + H2SO4 Na2SO4 + CO2 + H2OThese chemical methods can be effective in neutralizing the pH levels of lakes and rivers impacted by acid rain. However, it is essential to carefully monitor the dosage and application of these substances to avoid causing further harm to the aquatic ecosystem. Additionally, these methods should be combined with efforts to reduce the emission of pollutants that contribute to acid rain in the first place.