Suppose NaOH is added to the following system when it is at equilibrium.

NH3 (aq) + H2O (l) = NH4 (aq) + OH (aq)
a) in which direction will the reaction shift after the NaOH is added?
b) will this stress increase or decrease the value of the reaction quotient, Q?
C) will the rate of the forward reaction exceed the rate of the reverse reaction before equilibrium is reastablished?
D) when equilibrium is reastablished will the rate of the forward reaction exceed the rate of the reverse reaction?

Can you show me how to attempt this question?

I know that it will shift to the left to decrease the OH

Sure! Let's approach each part of the question step-by-step:

a) In which direction will the reaction shift after the NaOH is added?

To determine the direction of the shift, we need to consider Le Chatelier's principle. Adding NaOH, which dissociates into Na+ and OH-, introduces additional OH- ions to the system. Since OH- is a reactant on the left side of the equation, an increase in its concentration will drive the reaction to the right. Therefore, the reaction will shift towards the formation of NH4+ and OH-.

b) Will this stress increase or decrease the value of the reaction quotient, Q?

The reaction quotient, Q, is a measure of the concentrations of the reactants and products at any given moment in time, regardless of whether the system is at equilibrium or not. Adding NaOH will increase the concentrations of NH4+ and OH-, while NH3 and H2O concentrations remain unchanged. Consequently, the value of Q will increase since the products' concentrations increase.

c) Will the rate of the forward reaction exceed the rate of the reverse reaction before equilibrium is reestablished?

Adding NaOH will initially increase the concentration of OH-. This increase in OH- concentration will drive the reaction to the right, favoring the forward reaction. Therefore, in the short term, the rate of the forward reaction will exceed the rate of the reverse reaction before equilibrium is reestablished.

d) When equilibrium is reestablished, will the rate of the forward reaction exceed the rate of the reverse reaction?

At equilibrium, the rate of the forward reaction will be equal to the rate of the reverse reaction, and the concentrations of reactants and products will remain constant. Therefore, the rate of the forward reaction will not exceed the rate of the reverse reaction at equilibrium.

So, in summary:
a) The reaction will shift towards the formation of NH4+ and OH-.
b) The value of Q will increase.
c) The rate of the forward reaction will exceed the rate of the reverse reaction before equilibrium is reestablished.
d) The rate of the forward reaction will not exceed the rate of the reverse reaction at equilibrium.

To answer these questions, we need to consider the effect of adding NaOH to the system and how it will affect the equilibrium.

a) In this reaction, NaOH is a strong base that dissociates completely into Na+ and OH-. The Na+ ions won't have any effect on the equilibrium, but the OH- ions will react with the NH4+ ions to form more NH3 and H2O. This means that by adding NaOH, we are essentially increasing the concentration of OH- ions. According to Le Chatelier's principle, if we increase the concentration of a reactant or decrease the concentration of a product, the reaction will shift towards the right in order to restore equilibrium. Therefore, the reaction will shift to the right (forward direction) after NaOH is added.

b) The reaction quotient, Q, is the ratio of the concentrations of the products to the concentrations of the reactants, at any given moment during the reaction. When NaOH is added, the concentration of OH- ions increases, which will increase the concentration of the product NH4+. The concentration of the reactant NH3 and H2O remain the same. Since Q is calculated using the concentrations of the species present, adding NaOH will increase the value of Q.

c) Before equilibrium is reestablished, the reaction proceeds in both the forward and reverse directions, but their rates are not equal. When NaOH is added, the concentration of OH- ions increases, which means more NH4+ ions will be formed. This leads to an increase in the rate of the forward reaction. However, the rate of the reverse reaction also increases as NH3 reacts with OH-. Therefore, it's not possible to determine if the rate of the forward reaction will exceed the rate of the reverse reaction before equilibrium is reestablished.

d) When equilibrium is reestablished, the concentrations of NH3, H2O, NH4+, and OH- will stabilize, and the rates of the forward and reverse reactions will become equal. At equilibrium, the rate of the forward reaction will be equal to the rate of the reverse reaction.

I'll be happy to help. Tell me exactly what you don't understand about the question. Do you know what Q is? Do you know what equilibrium is?