Lime is an oxide of calcium(CaO). As a metallic oxide, it produces a basic solution when it reacts with water.
The main reason why lime is added to lakes is to reduce acidity in the lake water.
Bottom muds in lakes are usually acidic and makes the water hypertonic. When lime is added, it reduces the pH of the water and causes acidity to reduce.
Lime also helps to reduce the hardness of lake water to a good level.
Lime also helps to release nutrients useful for photosynthesis of plants in the lake.
If you change the subscripts it would change the reactants or products and then you would be solving a different formula, you would change what the chemical is
