# Water and salt

```Practice AND Review Answers
1. Identify as an acid or base or other and name:
a. Ca(OH)2 base/calcium hydroxide
h. H2CO3 carbonic acid
b. H2SO4 sulfuric acid
i. HNO3 nitric acid
c. HNO2 nitrous acid
j. H3PO4 phosphoric acid
d. Mg(OH)2 base/magnesium hydroxide
k. NaOH base/sodium hydroxide
e. CH4
neither/methane
l. H2SO3 sulfurous acid
f. HI
hydroiodic acid
m. NH3 base/ ammonia
g. CsOH base/ cesium hydroxide
n. NaBr neithersalt/ sodium bromide
2. In an acid is the hydrogen ion concentration higher than or lower than the
hydroxide ion concentration? Acid high H+ concentration, low OH- conc
3. Give me the hydrogen ion concentration range and pH range for acids and give
me the hydroxide ion range and pOH range for bases. pH = 0-7 Acid pH Base =
7-14 [H+] = 1X 10-7 to 1X 100
[OH-] = 1X 10-14 to 1X 10-7
4. What is the pH of a solution that has a hydrogen ion concentration of 2.5x10-5M.
What is the pOH of this solution? I think I messed up and had a positive
exponentpH = 4.6 pOH = 9.4
5. If the pOH of a solution is 13.0, what is the HYDROGEN ion concentration?
pH= 1 H+ conc =.1
6. The pH and pOH of a solution must add up to equal what? The hydrogen ion and
hydroxide ion concentrations of a solution must add up to equal what?
7. If the hydroxide ion concentration of a solution is 2.65x10-2, what is the hydrogen
ion concentration, pH, and pOH. Is this solution acidic of basic?
1.0X10-14 /2.65x10-2 = [H+] = 3.77x10-13
pOH=1.6 pH=12.4
8. Give the definitions of all three methods of defining acids and bases. (Arrhenius,
Bronsted Lowry, and Lewis) Look them up
9. Is NH3 an Arrhenius base? Is it a Bronsted Lowry base? Explain your answers.
Not Arrhenius base, No OH- present so can’t be Arrhenius, H+ion acceptor to become
NH4+
10. Identify the acid, base, conjugate acid, and conjugate base in the following
reactions.
a. HNO3 + H2O  H3O+ + NO3b. CO32- + H2O  HCO3- + OHAcid
base
CA
CB
Base Acid
CA
CB
+
+
CH3COOH + H2O  H3O + CH3COO d. H3PO4 + H2O  H + H2PO4Acid
base
CA
CB
Acid
base
CA CB
e. H2PO4- + H2O  H+ + HPO4211. Name 4 strong acids and 4 strong bases. Acids-hydrochloric, sulfuric,lemon
juice,phosphoric,stomach Bases- NaOH(lye), other hydroxides
12. What is the molarity of phosphoric acid if 50.0 mL of the solution is neutralized
by 45.2 mL of 0.25 M NaOH? Predict products and balance.
H3PO4 + 3NaOH  Na3PO4 + 3H2O
.25M = x/.0452liters NaOH
x= .0113 moles NaOH divided by 3 for mole ratio
.0038 mol acid/.050 liters = .076M H3PO4
13. How many moles of magnesium hydroxide are needed to completely neutralize
0.25 moles of nitric acid? Predict products and balance.
Mg(OH)2 + 2HNO3  Mg(NO3)2 + 2H2O
Mole ratio .25/2 = .125moles
14. How many mL of 3.0 M KOH are needed to prepare 870 mL if 0.20 M KOH?
M1V1=M2V2
3.0M(V2) = .20M(870mL)
V2=58mL
15. If you need 50.0 mL of 0.152 M HCl to neutralize 29.2 mL of Ca(OH)2, what is
the molarity of the base?
2HCl + Ca(OH)2 2 H2O + CaCl2
0.152M HCl = x moles/.050 liters
x= .0076 molesAcid
.0038 moles of base/ .0292liters = .13 Molar Ca(OH)2
.26
16. What is the molarity of a solution of base if 25.0 mL is neutralized by 75.0 mL of
0.40 m acid?
M1V1=M2V2
17. Define titration. Look it up
18. How many moles of potassium hydroxide are needed to completely neutralize
1.56 moles of phosphoric acid? Predict products and balance.
3KOH + H3PO4  K3PO4 + 3H2O
4.68 moles
19. How many moles of calcium hydroxide are needed to neutralize 6.30 moles of
nitric acid? Predict products and balance.
Ca(OH)2 + 2HNO3  Ca(NO3)2 + 2H2O 2:1 ratio 6.3 /2 = 3.15 moles
20. How many milliliters of 2.50M HCl must be added to 25.0 mL of 1.00M
potassium hydroxide to make a neutral solution? Predict products and balance.
HCl + KOH  KCl + H2O
1M = x/.025liters
x = .025 moles KOH
2.50 M = .025 mole HCl/ x liters
.01 liters = 10 milliliters
21. If the [H+] of a solution is 2.3X10-3, what is the pOH of this solution?
-log ( 2.3X10-3) = pH= 2.6 pOH= 11.4
22. What is always the product of an acid/base neutralization?
Water and salt
```