Chapter 10: Acids and Bases
Mini Investigation: The pH Rainbow Column, page 463
A. The colours observed in the test tube were purple (very basic with a pH of 10), blue
(moderately basic with a pH of between 7 and 10), green (neutral with a pH of 7), yellow
(moderately acidic with a pH of between 3 and 7), and red (very acidic with a pH of less than 3).
These pH values are approximate.
B. The greatest degree of neutralization occurred at the bottom of the test tube. The purple colour
of the solution at the bottom of the test tube indicated that the acid was neutralized and that the
solution contained an excess of sodium carbonate. Less neutralization occurred in the upper
portions of the test tube because less sodium carbonate reacted with the acid.
C. It was necessary to add the sodium carbonate solution from the top so that it could sink to the
bottom of the test tube and react with the acid along the way. This produced the gradual change
in colour. If the sodium carbonate solution had been added first to the test tube, the only colour
changes that could occur would be at the point of contact.
Section 10.1: Properties of Acids and Bases
Tutorial 1 Practice, page 468
1. (a) Step 1. Oxygen is not present.
Step 2. The acid with the formula HBr(aq) is hydrobromic acid.
(b) Step 1. Oxygen is present. It is an oxyacid
Step 2. The oxyanion is PO33–, phosphite ion.
Step 3. The acid with the formula H3PO3(aq) is phosphorous acid.
(c) Step 1. Oxygen is not present.
Step 2. The acid with the formula H2S(aq) is hydrosulfuric acid.
(d) Step 1. Oxygen is present. It is an oxyacid
Step 2. The oxyanion is SO32–, sulfite ion.
Step 3. The acid with the formula H2SO3(aq) is sulfurous acid.
(e) Step 1. Oxygen is present. It is an oxyacid
Step 2. The oxyanion is IO4–, periodate ion.
Step 3. The acid with the formula HIO4(aq) is periodic acid.
(f) Step 1. Oxygen is present. It is an oxyacid
Step 2. The oxyanion is FO–, hypofluorite ion.
Step 3. The acid with the formula HFO(aq) is hypofluorous acid.
2. (a) Step 1. Since the name contains the prefix hydro-, it is not an oxyacid.
Step 2. The acid contains the fluoride ion, F–.
Step 3. Using the zero-sum rule, one H+ ion is required to produce a neutral acid molecule.
Step 4. The formula of hydrofluoric acid is HF(aq).
(b) Step 1. Since the name does not contain the prefix hydro-, it is an oxyacid.
Step 2. Since the stem of the acid’s name is sulf- and the suffix is -ous, the acid contains the
sulfite ion, SO32–.
Step 3. Using the zero-sum rule, two H+ ions are required to produce a neutral acid molecule.
Step 4. The formula of sulfurous acid is H2SO3(aq).
(c) Step 1. Since the name does not contain the prefix hydro-, it is an oxyacid.
Step 2. Since the stem of the acid’s name is hypochlor- and the suffix is -ous, the acid contains
the hypochlorite ion, ClO–.
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Chapter 10: Acids and Bases
10.1-1
Step 3. Using the zero-sum rule, one H+ ion is required to produce a neutral acid molecule.
Step 4. The formula of hypochlorous acid is HClO(aq).
(d) Step 1. Since the name does not contain the prefix hydro-, it is an oxyacid.
Step 2. Since the stem of the acid’s name is brom- and the suffix is -ic, the acid contains the
perbromate ion, BrO4–.
Step 3. Using the zero-sum rule, one H+ ion is required to produce a neutral acid molecule.
Step 4. The formula of perbromic acid is HBrO4(aq).
Section 10.1 Questions, page 469
1. Chewy sour candies sometimes remain stuck to the teeth for several minutes, which is a
problem because they contain acids that gives the candy its sour taste and can prematurely wear
away teeth.
2. (a) HC2H3O2(aq) + NaHCO3(s) → CO2(g) + H2O(l) + NaC2H3O2(aq)
(b) Using sodium hydrogen carbonate and vinegar may be a greener alternative to using
household drain openers that contain sodium hydroxide because sodium hydrogen carbonate and
vinegar are less corrosive that sodium hydroxide. Sodium hydrogen carbonate and vinegar can be
safely handled without the need of protective safety equipment and they can be flushed down the
drain. The bubbling action of the carbon dioxide produced in this reaction may be helpful in
dislodging the materials that are responsible for the clogged drain.
3. (a) Since zinc and aluminum are above hydrogen on the activity series, these metals should
react with sulfuric acid. No reaction is expected with silver since silver is below hydrogen on the
activity series.
(b) H2SO4(aq) + Zn(s) → H2(g) + ZnSO4(aq)
3 H2SO4(aq) + 2 Al(s) → 3 H2(g) + Al2(SO4)3(aq)
4. (a) Step 1. Oxygen is present. It is an oxyacid
Step 2. The oxyanion is CO32–, carbonate ion.
Step 3. The acid with the formula H2CO3(aq) is carbonic acid.
(b) Step 1. Oxygen is not present.
Step 2. The acid with the formula HI(aq) is hydroiodic acid.
(c) Step 1. Oxygen is not present.
Step 2. The acid with the formula H2S(aq) is hydrosulfuric acid.
(d) Step 1. Oxygen is present. It is an oxyacid
Step 2. The oxyanion is PO43–, phosphate ion.
Step 3. The acid with the formula H3PO4(aq) is phosphoric acid.
(e) Step 1. Oxygen is present. It is an oxyacid
Step 2. The oxyanion is NO3–, nitrate ion.
Step 3. The acid with the formula HNO3(aq) is nitric acid.
(f) Step 1. Oxygen is not present.
Step 2. The acid with the formula HF(aq) is hydrofluoric acid.
(g) Step 1. Oxygen is present. It is an oxyacid
Step 2. The oxyanion is NO2–, nitrite ion.
Step 3. The acid with the formula HNO2(aq) is nitrous acid.
(h) Step 1. Oxygen is present. It is an oxyacid
Step 2. The oxyanion is SO32–, sulfite ion.
Step 3. The acid with the formula H2SO3(aq) is sulfurous acid.
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Chapter 10: Acids and Bases
10.1-2
(i) Step 1. Oxygen is present. It is an oxyacid
Step 2. The oxyanion is PO33–, phosphite ion.
Step 3. The acid with the formula H3PO3(aq) is phosphorous acid.
(j) Step 1. Oxygen is present. It is an oxyacid
Step 2. The oxyanion is IO43–, periodate ion.
Step 3. The acid with the formula HIO4(aq) is periodic acid.
(k) Step 1. Oxygen is present. It is an oxyacid
Step 2. The oxyanion is ClO–, hypochlorite ion.
Step 3. The acid with the formula HClO(aq) is hypochlorous acid.
5. The presence of hydrogen atoms at the start of the chemical formula and the (aq) symbol at the
end of the formula indicate that the compound is likely to be an acid.
6. (a) Step 1. Since the name contains the prefix hydro-, it is not an oxyacid.
Step 2. The acid contains the bromide ion, Br–.
Step 3. Using the zero-sum rule, one H+ ion is required to produce a neutral acid molecule.
Step 4. The formula of hydrobromic acid is HBr(aq).
(b) Step 1. Since the name does not contain the prefix hydro-, it is an oxyacid.
Step 2. Since the stem of the acid’s name is chlor- and the suffix is -ic, the acid contains the
perchlorate ion, ClO4–.
Step 3. Using the zero-sum rule, one H+ ion is required to produce a neutral acid molecule.
Step 4. The formula of perchloric acid is HClO4(aq).
(c) Step 1. Since the name does not contain the prefix hydro-, it is an oxyacid.
Step 2. Since the stem of the acid’s name is chlor- and the suffix is -ous, the acid contains the
chlorite ion, ClO2–.
Step 3. Using the zero-sum rule, one H+ ion is required to produce a neutral acid molecule.
Step 4. The formula of chlorous acid is HClO2(aq).
(d) Step 1. Since the name contains the prefix hydro-, it is not an oxyacid.
Step 2. The acid contains the iodide ion, I–.
Step 3. Using the zero-sum rule, one H+ ion is required to produce a neutral acid molecule.
Step 4. The formula of hydroiodic acid is HI(aq).
7. (a) Mg(OH)2(aq) is magnesium hydroxide.
(b) KOH(aq) is potassium hydroxide.
8. The chemical formula for chloric acid is HClO3(aq) and the chemical formula for hydrochloric
acid is HCl(aq). The formulas are the same in that they both contain one hydrogen atom and one
chlorine atom, and they are both in the aqueous state. Chloric acid contains three oxygen atoms
while hydrochloric acid does not contain any oxygen.
9. (a) The chemical formula of iodic acid is HIO3(aq).
(b) The chemical formula of iodous acid is HIO2(aq). The chemical formula of hypoiodous acid
is HIO(aq).
10. Hydrochloric acid is secreted by specialized cells in the inner cell layer of the stomach lining
called parietal cells. The stomach lining is made of epithelial cells that secrete a protective layer
of mucus, which prevents the acid from attacking the stomach lining. The epithelial cells also
secrete hydrogen carbonate (also called bicarbonate) ions to neutralize any hydrochloric acid that
may penetrate the mucous layer.
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Chapter 10: Acids and Bases
10.1-3
11. Heartburn is a burning sensation in the chest or throat caused by stomach acid leaking into
the esophagus, the tube that links to throat to the stomach. A number of factors contribute to
heartburn including certain foods, pregnancy, consumption of alcohol, and certain medications.
Antacids provide short-term relief to heartburn. However, for long-term relief, the factor that
causes heartburn must be avoided. In some cases, the damage caused by heartburn must be
surgically repaired.
12. The process of a cave formation in limestone deposits begins with ground water carrying
dissolved carbon dioxide that seeps into the limestone deposit. The reaction of carbon dioxide
and water forms a mildly acidic solution of carbonic acid. Limestone deposits consist mostly of
carbonate compounds, which react readily with acids. As acidified ground water seeps through
cracks in the rock, it reacts with limestone, eroding the rock to form caves. Large caves take
millions of years to form.
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Chapter 10: Acids and Bases
10.1-4