Please Help 2.) An experiment similar to the one performed was done in order to
ID: 560238 • Letter: P
Question
Please Help
2.) An experiment similar to the one performed was done in order to determine the Kap of Ba(OH)2. In this instance, a strong acid, HCI is placed in the buret and a titration performed. Using the data provided, complete the remaining entries in the table a. Write the solubility equation of Ba(OH)2(s) in water b. Write the Ksp expression for this equilibrium. c. Write the reaction that occurs when HCI is added. d. If phenolphthalein is used as an indicator, describe the appearance of the solution prior to and at the endpoint.Explanation / Answer
a) write the solubility equation of Ba(OH)2 in water
Barium hydroxide dissociates into Ba2+ and OH- ions;
therefore, the solubility equation for Ba(OH)2 in water is:
Ba(OH)2(s)Ba2+(aq)+2OH(aq)
b) write the Ksp expression for this equation
From the equation above, one mole of Ba(OH)2 produces 1 mole of Ba2+ and 2 moles OH- ions.
Therefore, the solubility product constant Ksp:
Ksp = [Ba2+][OH-]2
c) write the reaction that occurs when HCl is added
Ba(OH)2 is a strong base and HCl is a strong acid. Therefore, it is a neutralization reaction and produces water.
Hence, the reaction is:
Ba(OH)2(aq) + 2HCl (aq) ---> BaCl2 (aq) + 2H2O (l)
d) if the phenolphthalein is used as an indicator describe the appearance of the solution prior to and at the endpoint
Phenolphthalein has pink color at basic conditions (pH >8 ). And at acidic pH, the indicator color show no color(colorless).
Therefore, our reaction mixture initially is basic (Ba(OH)2 is strong base), therefore, the color of solution will be
pink before the titration with HCl.
At the endpoint, the pink color disappears because the solution will become acidic.