1. A C I D - B A S E T I T R A T I O N A N D p H
Checking Ch 15.1
A C I D - B A S E
T I T R A T I O N A N D p H

2. 1. Amphoteric:
What is the concentration of hydronium ions in pure water at 25°C?
a. 0.1M
b. 10-7M
c. 10+7M
d M

3. 2. Distilled water contains
A.H2O.
B. H3O+.
C. OH−.
D. All of the above

4. 3. What is the pH of a M HNO3?
A. 1.0
B. 3.0
C. 4.0
D. 5.0

5. 4. Which of the following solutions would have a pH value greater than 7?
A. [OH−] = 2.4 × 10−2 M
B. [H3O+] = 1.53 × 10−2 M
C M HCl
D. [OH−] = 4.4 × 10−9 M

6. 5. If the pH of a solution of the strong base NaOH is known, which property of the solution can be calculated?
A. molar concentration
B. [OH−]
C. [H3O+]
D. All of the above

7. 6. A neutral aqueous solution
A. has a 7.0 M H3O+ concentration.
B. contains neither hydronium ions nor hydroxide ions.
C. has an equal number of hydronium ions and hydroxide ions.
D. None of the above

8. 7. Identify the salt that forms when a solution of H2SO4 is titrated with a solution of Ca(OH)2.
A. calcium sulfate
B. calcium hydroxide
C. calcium oxide
D. calcium phosphate

9. 8. Which of the following is a strong acid?
a. HF
b. HBrO3
c. CH3COOH
d. HBr

10. 9. The pH of a solution is 6.32. What is the pOH?
B. 4.8 × 10−7
C. 7.68
D. 2.1 × 10−8
Strong Acids
List of the Strong Acids
These are the strong acids. What makes them 'strong' is that completely dissociate into their ions (H+ and an anion) when they are mixed with water. Any other acid is a weak acid. There are only six strong acids, so you might want to commit the list of strong acids to memory. HCl - hydrochloric acid HNO3 - nitric acid H2SO4 - sulfuric acid HBr - hydrobromic acid HI - hydroiodic acid (also known as hydriodic acid) HClO4 - perchloric acid
As the strong acids become more concentrated, they may be unable to fully dissociate. The rule of thumb is that a strong acid is 100% dissociated in solutions of 1.0 M or less.
About:
The relative stability of the conjugate base of the acid determines its acidity.
Lactic acid (IUPAC systematic name: 2-hydroxypropanoic acid), also known as milk acid, is a chemical compound that plays a role in several biochemical processes. It was first isolated in 1780 by a Swedish chemist, Carl Wilhelm Scheele, and is a carboxylic acid with a chemical formula of C3H6O3. It has a hydroxyl group adjacent to the carboxyl group, making it an alpha hydroxy acid (AHA). In solution, it can lose a proton from the acidic group, producing the lactate ion CH3CH(OH)COO−. It is miscible with water or ethanol, and is hygroscopic.

11. 10. The Kw value for water can be affected by
A. dissolving a salt in the solution.
B. changes in temperature.
C. changes in the hydroxide ion concentration.
D. the presence of a strong acid.

12. 11. Which of the pH levels listed below is the most acidic?
A. pH = 1
B. pH = 5
C. pH = 9
D. pH = 13

13. 12. A solution has a pH of 4.75. What is the hydronium ion concentration?
a x 104
b x 10-5
c x 101
d x 10-10

14. 13. What is the concentration of hydronium ions in pure water?
a M b.
c. the same as [OH-]
d. All of the above

15. 1. Calculating pH from [H3O+]
pH = −log [H3O+] practice 15C #1 (p506)
What is the pH of a solution if the [H3O+] is 6.7 × 10−4 M?
(key strokes for TI 80’s)
Change the sign (+/−); Key log; key in the number: 6.7;
2nd/log key in exponent-4 enter; pH = 3.17; pOH = do the other three include the pOH
[OH-] = (1.0 x 10-14)/ [H3O] = [OH-] = (1.0 x 10-14)/ [6.7 × 10−4 ]=1.43x10-11 M
Calculating [H3O+] from pH
Determine [H3O+] M from pH 3.67 ; pOH = ( )= 10.33
[H3O+]=2nd log, key in 3.67 enter = 4.68x10-3M
[OH] = (1.0 x 10-14)/ [H3O] = [OH-] = ( 1.0 x )/ [ 4.68x10-3 ]=2.14x10-12 M

16. 2. Calculating [H3O+] from pH
If you rearrange pH = −log [H3O+] to solve for [H3O+], the equation becomes
[H3O+] = 10−pH
• Change the sign of the pH (+/−)
• Raise 10 to the negative pH power (take the antilog).
• The result is [H3O+].
So lets find the concentrations of KOH, a strong base, from the pOH of 3.45; answer:
pH=10.55; basic, alkaline; [H3O+]=2.818x10-11 M; pOh=3.45; [OH-]=3.55x10-4M