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Unformatted text preview: of oxides: the normal oxide, the peroxide, and the superoxide.
•Method of Solution
Normal oxides contain the O 2– ion in which oxygen has an oxidation state of –2. Peroxides contain an oxygen2–
oxygen bond. Metal peroxides are ionic and contain the O2 ion. Hydrogen peroxide is a covalent peroxide
(H—O—O—H) with oxygen in the –1 oxidation state. The superoxide ion O 2 has oxygen in the –1/2
EXAMPLE 21.6 Oxidation Numbers of Sulfur
List the known oxidation numbers of sulfur and write the formula of a compound or ion that exemplifies each
•Method of Solution
S 2 Cl 2
sulfur (the element)
16. Back Which is a stronger oxidizing agent, diatomic oxygen or ozone?
What is the principle use of O2 in the United States?
What is the oxidation number of O in H2 O2 , H 2 O and O2 ?
Hydrogen peroxide can decompose by a disproportionation reaction. Write the equation for this reaction.
Write formulas of oxide, peroxide, and superoxide compounds that include a metal.
Starting with elemental sulfur, S(s), show the steps needed to prepare sulfuric acid. Forward Main Menu TOC Study Guide TOC Textbook Website MHHE Website Nonmetallic Elements and Their Compounds / 4 25 THE HALOGENS
2. Write chemical equations to show the preparations of the halogens.
Describe the chemical properties and give the major uses of these elements and their compounds. Occurrence and Preparation. The elements in Group 7 are called the halogens. In the elemental state
they form diatomic molecules, X2 . Because of their high reactivity the halogens are always found combined
with other elements. Chlorine, bromine, and iodine occur as halides in seawater, and fluorine occurs in the
minerals fluorspar (CaF2 ) and cryolite (Na3 AlF 6 ).
Fluorine is prepared by the electrolysis of liquid HF at 70°C.
electrolysis 2HF(l) → H 2 (g) + F2 (g)
Chlorine is prepared industrially by the electrolysis of a concentrated aqueous NaCl solution (brine). This is
called the chlor-alkali process (NaOH is the alkali).
electrolysis 2NaCl(aq) + 2H2 O(l) → 2NaOH(aq) + H2 (g) + Cl2 (g)
Because chlorine is a stronger oxidizing agent than bromine or iodine, free Br2 and I2 can be generated by
bubbling Cl2 gas through solutions containing bromide and iodide ions.
Cl 2 (g) + Br– (aq) → 2Cl– (aq) + Br2 (l)
Cl 2 (g) + 2I – (aq) → 2Cl– (aq) + I2 (s)
Chlorine, bromine, and iodine can be prepared in the laboratory by heating the corresponding alkali halides in
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