what will the pH at the end point of 0.0812M Ba(OH)2 be when titrated with HCl?
a) 9.0
b) 8.0
c) 12.2
d) 7.0
e) 6.0
for this question, can i just assume the pH will be 7 since it's s titration with a strong base and a strong acid? (or do i have to do calculations?) I'm just wondering, i'm studying for an exam and i happen to be a slow worker looking for fast short cuts. thank you for your time!
If the exam is a multiple guess (multiple choice by other names), I would pick 7.0 automatically since I know BaCl2 is the salt of a strong base and a strong acid and that neither the cation nor the anion are hydrolyzed in aqueous solution. However, if the exam wants to see work, I think you must go through an explanation must like I've provided above.
thanks again!
To determine the pH at the end point of the titration, you need to consider the stoichiometry and equilibrium of the reaction between the strong base, Ba(OH)2, and the strong acid, HCl.
Ba(OH)2 and HCl react in a 1:2 ratio, meaning that for every 1 mole of Ba(OH)2, you need 2 moles of HCl. This reaction forms BaCl2 (barium chloride) and water (H2O).
The key to finding the pH at the end point is recognizing that barium chloride is a sparingly soluble salt and dissociates in water to produce barium ions (Ba2+) and chloride ions (Cl-). The hydrolysis of the barium ions generates hydroxide ions (OH-) and contributes to the pH of the solution.
Since Ba(OH)2 is a strong base, it fully dissociates in water to produce 2 moles of OH- for every mole of Ba(OH)2.
Now, let's consider the pH at the equivalence point. At this point, the moles of HCl added would be stoichiometrically equal to the moles of Ba(OH)2.
The balanced equation for the reaction is:
Ba(OH)2 + 2HCl -> BaCl2 + 2H2O
At the equivalence point, all the Ba(OH)2 has reacted with HCl, and we are left with only the products. The Ba2+ ions will react with the hydroxide ions generated from its own hydrolysis, resulting in the formation of water and shifting the equilibrium towards the reactants (OH- and Ba(OH)2). This means that OH- ions will still be present in the solution even though the reaction is complete.
Therefore, the pH at the end point will be greater than 7, indicating it is more basic. So, options (a) 9.0, (b) 8.0, (c) 12.2, and (d) 7.0 could all potentially be correct.
To determine the exact pH value, you would need to calculate the concentration of the remaining hydroxide ions (OH-) in the solution using the initial concentration of Ba(OH)2 and the volume of HCl added during the titration.
Given the provided concentrations of Ba(OH)2 and HCl, you would need to perform the necessary calculations to obtain the accurate pH value. If you have access to a calculator and enough time, it is best to calculate the pH rather than making assumptions.
I understand that time might be a constraint during exams, but it is crucial to employ proper calculations whenever possible to ensure accurate answers. It's always better to opt for a more reliable approach, especially in a rigorous academic setting.