QUESTION 3
a) First we calculate the OH- concentration using the following equation.
Consider the following equilibrium between the base B and water.
Note that the concentrations of BH+ and OH- are equal. The equation for Kb can be written as,
Substituting the concentrations,
We assume that 0.345M-2.45*10-5M is approximately equal to 0.345M.
b) Consider the above equilibrium,
BH+ can dissociate to give,
Therefore, the Ka equation can be given as,
For a conjugate acid-base pair, we can write,
c) Online sources state that the Kb value of pyridine is 1.7*10-9. Thus the identity is most likely to be pyridine.
d) The following equation can be used to determine the volume required to reach the equivalence point.
3. The pH of a 0.345 M weak base solution is 9.39. 50.0 mL of the...
(10 marks) Calculate the pH after titrating 50.0 mL of a 0.100 M weak base solution (Kb = 7 x10-9) with: 0.200 M HBr to the equivalence point b. 50.0 mL of 0.200 M HBr
Consider the titration of 50.0 mL of 0.133 M NH3 (a weak base with Kb = 1.76 x 10-5 ) with 0.223 M HCl (a strong acid). Calculate the pH of the solution at each of the following points: 1. What is the pH of the solution before the titration is begun? 2. What is the pH of the solution after the addition of 15 mL of HCl? 3. What is the pH of the solution at the equivalence point?...
3. Weak Base versus Strong Acid Derive a titration curve for the titration of 50.0 mL of 0.10 M NH3 (Kb=1.8 x 10-5) with 0.25 M HCl. Calculate the pH for the following volumes of HCl (0 mL, 10 mL, 15 mL, 20 ml, 25 mL, 30 mL, 35 mL). Volume of HCI, in milliters 0 pH (a) 10 15 (d) 20 |(f) 25 30 35 (g) pH at the equivalence point Specify your choice of indicator
You have 15.00 mL of a 0.100 M aqueous solution of the weak base C5H5N (Kb = 1.50 x 10-9). This solution will be titrated with 0.100 M HCl. (a) How many mL of acid must be added to reach the equivalence point? (b) What is the pH of the solution before any acid is added? (c) What is the pH of the solution after 10.00 mL of acid has been added? (d) What is the pH of the solution...
You have 25.00 mL of a 0.100 M aqueous solution of the weak base CH3NH2 (Kb = 5.00 x 10-4). This solution will be titrated with 0.100 M HCl. (a) How many mL of acid must be added to reach the equivalence point? (b) What is the pH of the solution before any acid is added? (c) What is the pH of the solution after 5.00 mL of acid has been added? (d) What is the pH of the solution...
Sera titrates a 10.00 mL sample of a 0.0750 M weak base (A4-) with 0.2500 M HCl, a strong monoprotic acid. The Kb values for this base are Kb1 = 2.00 x 10-3, Kb2 = 3.00 x 10-6, Kb3 = 4.00 x 10-9, and Kb4 = 5.00 x 10-11. Calculate the volume of HCL, in mL, needed to reach the first equivalence point of this titration. Calculate the pH of the titration solution after 4.50 mL of HCl has been...
A. Match each type of titration to its pH at the equivalence point. Weak acid, strong base Strong acid, strong base Weak base, strong acid pH less than 7 pH equal to 7 pH greater than 7 B. A 56.0 mL volume of 0.25 M HBr is titrated with 0.50 M KOH. Calculate the pH after addition of 28.0 mL of KOH. C. Consider the titration of 50.0 mL of 0.20 M NH3 (Kb=1.8 x 10^-5) with 0.20 M HNO3....
50.0 mL sample of the weak acid the concentration of the weak acid = 0.15 M 25 mL of the week acid into 100 mL beaker titrated this solution of 0.21 M NaOH moles of weak acid = 3.75*10^-3 moles of NaOH = moles of week acid c) How many milliliters of the NaOH are required to neutralize the sample of weak acid? d) How many moles of NaOH have been added at one half of the volume in part...
1. Consider the titration of 50.0 mL of 0.200 M HNO3 with 0.100 M NaOH solution. What volume of NaOH is required to reach the equivalence point in the titration? a. 25.0 mL b. 50.0 mL c. 1.00 × 10^2 mL d. 1.50 × 10^2 mL 2. Consider the following acid–base titrations: I) 50 mL of 0.1 M HCl is titrated with 0.2 M KOH. II) 50 mL of 0.1 M CH3COOH is titrated with 0.2 M KOH. Which statement...
You have 40.00 mL of a 0.300 M aqueous solution of the weak base C6H5NH2 (Kb = 4.00 x 10-10). This solution will be titrated with 0.300 M HCl. (a) How many mL of acid must be added to reach the equivalence point? (b) What is the pH of the solution before any acid is added? (c) What is the pH of the solution after 10.00 mL of acid has been added? (d) What is the pH of the solution...