Consider the following equilibrium for nitrous acid, HNO2, a weak acid: HNO2 (aq) + H2O (l) - >< - H3O + (aq) + NO2^ - (aq) In which direction will the equilibrium shift if NaOH is added?

The equilibrium will shift to the right

Explanation:

The chemical equilibrium represents a balance between direct and inverse reactions.

The Le Chatelier Principle states that variations in experimental conditions can alter this balance and displace the equilibrium position, causing more or less of the desired product to form. And in this way the system evolves in the opposite direction so as to counteract the effects of such disturbance.

The variation of one or more of the following factors are those that can alter the equilibrium condition:

Temperature The pressure The volume The concentration of reactants or products

In this case:

NaOH produces OH⁻ ions. OH⁻ ion uses up H₃O⁺ through the reaction:

H₃O⁺ + OH⁻ → 2 H₂O

According to the Le Chatelier principle, the addition of NaOH consumes one of the products, decreasing its concentration. Therefore, to balance the reaction, the equilibrium will shift to the right in order to counteract the effect that disturbed it and recover the equilibrium state.