Acid rain is created when water vapor in the atmosphere absorbs carbon dioxide barium sulfur sulfur oxide

Sulfur oxides

Explanation:

Sulfur oxides (mainly sulfur dioxide in this case) are produced when fossil fuels are burnt in industrial sources like power stations, factories, incinerators etc, as most fuels sulfur as impurities. Sulfur reacts with the oxygen in the air during combustion, thus giving off sulfur dioxides.

When these sulfur dioxide reacts with the rainwater (or water vapor in the atmosphere), they form sulfurous acid, or even sulphuric acid if sulphurous acid further reacts with oxygen. These acids cause the rain to become more acidic than normal.

The reaction is outlined below:

SO2(g) + H2O(l) ⇌ H2SO3(aq)

The reason why carbon dioxide isn't the correct answer (as CO2 is an acidic gas too) is because rain should naturally be slightly acidic (pH 5.6) due to carbon dioxide reacting with rainwater to form carbonic acid. Speaking of the harm of carbon dioxide, it should not be classified as a pollutant generally.

a. energy is absorbed in the reaction.

if in a given reaction the energy of products is greater than the energy of reactants it means that reaction is endothermic and during the reaction, the energy is absorbed by reactants. in an endothermic reaction, the products have more stored chemical energy than the reactants. and in this reaction the reactants are more stable than products before the compounds with less energy are always more stable.

o conteúdo de calor de um sistema é igual à entalpia apenas para um sistema que é constante