Study of the Weak-Acid Equilibrium: HSO_4^-(aq) + H_2O(l) - H_3O^+ (aq) + SO_4^2
ID: 952460 • Letter: S
Question
Study of the Weak-Acid Equilibrium: HSO_4^-(aq) + H_2O(l) - H_3O^+ (aq) + SO_4^2-(aq) When adding sodium sulfate solution, how did the color of the equilibrium mixture change? The color change indicated a shift in the point of equilibrium. In which direction did the equilibrium shift? Explain your answer to question 1a. You should indicate which ion was added to or removed from the equilibrium mixture. When adding sodium hydrogen sulfate crystals, how did the color of the equilibrium mixture change? The color change indicated a shift in the point of equilibrium. In which direction did the equilibrium shift? left right Explain your answer to question 2a. You should indicate which ion was added to or removed from the equilibrium mixture. Upon heating in which direction is the equilibrium shifting? left right Upon cooling in which direction is the equilibrium shifting? left right Is the forward reaction endothermic exothermic Explain your answers to questions 3. 4, and 5.Explanation / Answer
1
When you added Na2SO4, you shifted the equilibirum to the left, this is because you added an excess of SO4, thus it is necessary to reduce the excess and form new HSO4 to restablish equilibrium.
2.
This is the opposite case, by adding HSO4 you shifted the equilibrium to the right, the excess of HSO4 ions added should react whith water to restablish equilibrium.
3
When you add heat, you are providing energy to the reaction in order to procede in the desire direction, hence when you heated the solution shifted to the left, to procede to the left direction you need energy (in this case in the form of heat), thus it is an endothermic reaction.
When you cool the solution, you are forcing the reaction to release energy (in the form of heat), this is the case of exothermic reactions.
So if you are saying that the reaction shifted to the right upon cooling it, the reaction is exothermic, because it is realising heat.