Titrations
Consider the titration of 75 mL of 0.35 M HCl with 0.25 M NaOH. What is the pH at the equivalence point?
pH = 7
Strong acid strong base
What is point A?
Equivalence point
Consider the titration of 50.0 mL of 2.0 M HNO2 (Ka = 4.0x10-4) with 1.0 M KOH. Create an Ice table but do not solve it.
[HNO2] [NO2] [H3O+]
2.0 0 0
-x +x +x
2.0 – x +x +x
Describe the acidity/basicity of a solution made when dissolving KCl in water. (Basic, Acidic, Neutral)
Neutral, KOH and Hal strong base and strong acid.
The pOH for a solution with [H3O+] = 2.5 x 10-5 M is 9.4.
True
Consider the titration of 105 mL of 0.45 M weak acid (Ka = 5.0 x 10-5) with 0.55 M strong base. What is the pH after the addition of 80 mL of strong base?
pH = 3.17
What is the pink Region?
Buffer region
Create an ICE table but do not solve for a solution that contains 0.139 M acetic acid
HC2H3O2(aq) = H+(aq) + C2H3O2-(aq)
HC2H3O2(aq) = H+(aq) + C2H3O2-(aq)
.139 0 0
-x +x +x
.139-x x x
HOBr
HOBrO3
HOBrO2
Which is the strongest acid?
HOBrO3
Most O atoms when molecules are the same but different # of O atoms
HNO3 and CH3COOH could function as a buffer solution.
False. needs to be weak acid/base and strong acid/base depending on the first compound. Strong acid and weak acid.
Consider the titration of 100 mL of 0.60 M weak acid (Ka = 3.6 x 10-5) with 0.70 M strong base. What is the pH after the addition of 50 mL of strong base?
pH 4.3
What is being titrated?
a base
Find the pH of a 0.275 M hypochlorous (HClO) acid solution. Ka = 3.0 x 10-8.
HClO = H+ + ClO-
.275 0 0
-x +x +x
.275-x +x +x
3x10-8=x2/(.275-x) assume x is small
x = 9.08x10-5
pH = - log (9.08 x 10-5) = 4.042
Describe the acidity/basicity of a solution made when dissolving NH4Br in water. (Acidic, Basic, Neutral)
Acidic NH4- weak base Br- Strong acid
The pH of a 0.30 M solution of benzoic acid is 5.22. Ka of benzoic acid = 6.6x10-5
False the pH = 3.99
Consider the titration of 235 mL of 0.45 M weak acid (Ka = 4.8 x 10-5) with 0.15 M strong base. What is the pH after the addition of 120 mL of strong base?
pH 3.63
What should the X axis be?
Volume of acid added
The acid dissociation constant (Ka) for benzoic acid is 6.3 x 10-5. Find the pH of a 0.35 M solution of benzoic acid.
HC7H3O2(aq) = H+ + C7H3O2-(aq)
.35 0 0
-x +x +x
.35-x +x +x
6.3 x 10-5= x2/(.35-x) assume x is small
x = 4.7 x 10-3
pH = - log (4.7 x 10-3) = 2.33
Which of the following is a Lewis acid, but not a Bronsted-Lowry acid?
A) CH3NH2 B) CH3COOH C) HNO3 D) H2O E) BCl3
BCl3
H2SO4 and H4SO4 are conjugate acids/bases.
False
onsider the titration of 125 mL of 0.55 M weak acid (Ka = 4.9 x 10-5) with 0.35 M strong base. What is the pH after the addition of 75 mL of strong base?
pH=4.1
What should the Y axis be?
pH
A 10.0-mL sample of 0.50 M NH3 is titrated with 0.50 M HCl. What is the pH of the solution after 10.0 mL of HCl has been added? This is the equivalence point! Ka of NH4+ = 5.6 x 10–10
pH = 4.9
Nitrous acid has a Ka of 4.0 x 10–4. It would be most effective for preparation of a buffer with a pH of 1, 3, 5, 7, or 9
3. pka=-log(Ka) pH=pka
= 3.4 round to 3
According to Brønsted and Lowry the conjugate acid of CH3OH is CH3OH2+
True! the base accepts a proton!