Calculate the pH of a buffer prepared by the addition of 0.50 moles of sodium nitrite (NaNO2) to a 150.0 mL of 0.125 M nitrous acid (HNO2). Ka (HNO2) = 4.6 × 10-4

The answer is c) pyrite

In reversible reaction chemistry equilibrium is attained when the forward and reverse reactions are taking place at the same rate, thus, the concentrations of reactants and products remain the same. a reversible reaction is a chemical reaction where the reactants form products that, in turn, react together to give the reactants back. in irreversible reactions on the other hand, the reactants react to form the products, which cannot revert back into reactants.