Chlorine oxidation numbers

Oxygen (each) Chlorine Oxidation number (-2) Oxidation number (+5)... 

A redox reaction the chlorine oxidation number decreases from zero to -1 the bromine or iodine oxidation number increases from -1 to zero. 

If the alkali is KOH, crystals of KCIO3, potassium chlorate, are deposited on cooling because it is sparingly soluble. The chlorate ion is pyramidal (Structure 6.5) in accordance with VSEPR theory the chlorine oxidation number is +5. Bromine and iodine behave in a similar way to chlorine, except that BrO" and lO" disproportionate much more easily than CIO" in the alkaline solution. The result is that the reaction of these elements with hot or cold alkali produces bromates or iodates. 

Anhydride of chloric acid, Cl20, is unknown. Oxides with even number of oxygen atoms are mixed anhydrides. Other chlorine oxides such as the radicals CIO, CIO, and CIO are known. Chlorine monoxide [14989-30-17, CIO, plays a key role in depletion of the o2one layer. 

The chlorine oxides are anhydrides or mixed anhydrides of the chlorine oxo-acids oxides with an odd number of oxygens are simple anhydrides whereas those with an even number are mixed anhydrides. 

Cyanides are dangerously toxic materials that can cause instantaneous death. They occur in a number of industrial situations but are commonly associated with plating operations, and sludges and baths from such sources. Cyanide is extremely soluble and many cyanide compounds, when mixed with acid, release deadly hydrogen cyanide gas. Cyanide is sometimes formed during the combustion of various nitrile, cyanohydrin, and methacrylate compounds. Cyanides (CN ) are commonly treated by chlorine oxidation to the less toxic cyanate (CNO ) form, then acid hydrolyzed to COj and N. Obviously, care should be taken that the cyanide oxidation is complete prior to acid hydrolysis of the cyanate. 

The oxidation number of an element in a monatomic ion is equal to the charge of that ion. In the ionic compound NaCl, sodium has an oxidation number of +1, chlorine an oxidation number of — 1. The oxidation numbers of aluminum and oxygen in A1203 (Al3+, O2- ions) are +3 and —2, respectively. 

When several oxidation numbers are found for the same element, they often differ from each other by jumps of one unit. For example, in the case of vanadium the common oxidation numbers form a continuous series from +2 to +3 to +4 to 4-5. Compare this with the halogens (Chapter 19). In the case of chlorine, for example, the common states are —1, +1, 4-3, 4-5, and 4-7 (jumps of two units instead of one unit). 

The oxidation number of an element in a monatomic ion is the same as its charge. For example, the oxidation number of magnesium is +2 when it is present as Mg2+ ions, and the oxidation number of chlorine is — 1 when it is present as Cl" ions. The oxidation number of the elemental form of an element is 0 so magnesium metal has oxidation number 0 and chlorine in the form of Cl2 molecules also has oxidation number 0. When magnesium combines with chlorine, the oxidation numbers change as follows ... 

Self-Test K.2A Find the oxidation numbers of sulfur, phosphorus, and chlorine in (a) H2S (b) P406 (c) CIO". 

Chlorine can exist in both positive and negative oxidation states. What is the maximum (a) positive and (b) negative oxidation number that chlorine can have (c) Write the electron configuration for each of these states, (d) Explain how you arrived at these values. 

The acid strengths and oxidizing abilities of the halogen oxoacids increase with the oxidation number of the halogen. The hypohalous acids, HXO (halogen oxidation number +1), are prepared by direct reaction of the halogen with water. For example, chlorine gas disproportionates in water to produce hypochlorous acid and hydrochloric acid ... 

The principal use of sodium chlorate is as a source of chlorine dioxide, C102. The chlorine in C102 has oxidation number +4, and so the chlorate must be reduced to form it. Sulfur dioxide is a convenient reducing agent for this reaction ... 

Perchloric acid, HC104, is prepared by the action of concentrated hydrochloric acid on sodium perchlorate, followed by distillation. It is a colorless liquid and the strongest of all common acids. Because chlorine has its highest oxidation number, +7, in these compounds, they are powerful oxidizing agents contact between perchloric acid and even a small amount of organic material can result in a dangerous explosion. 

The interhalogens have properties intermediate between those of the constituent halogens. Nonmetals form covalent halides metals tend to form ionic halides. The oxoacids of chlorine are all oxidizing agents both acidity and oxidizing strength of oxoacids increase as the oxidation number of the halogen increases. 

NaOCl Sodium hypochlorite is ionic, containing Na cations and OCl anions. The sodium cation has oxidation number equal to its charge, +1. In the anion, oxygen is -2 (Guideline 4), so chlorine must be +1 for the sum of the oxidation numbers to match the -1 charge of the hypochlorite anion (Guideline 2). 

CIF3 Fluorine is the more electronegative atom, so each fluorine atom has an oxidation number of-1 (Guideline 4). For the sum of the oxidation numbers to be zero (Guideline 2), chlorine must be +3. 

The redox reaction above can be used to determine the change in oxidation numbers for chlorine and silicon. According to this equation, what changes occurred ... 

The oxidation number of every halogen atom in its compounds is - 1 except for a chlorine, bromine, or iodine atom combined with oxygen or a halogen atom higher in the periodic table. For example, the chlorine atoms in each of the following compounds have oxidation numbers of -1 ... 

The chlorine atom in each of the following has an oxidation number different from - 1 ... 

EXAMPLE 13.1. What are the oxidation numbers of chlorine and iodine in ICl, ... 

The rules above gave maximum and minimum oxidation numbers, but those might not be the only oxidation numbers or even the most important oxidation numbers for an element. Elements of the last six groups of the periodic table for example may have several oxidation numbers in their compounds, most of which vary from each other in steps of 2. For example, the major oxidation states of chlorine in its compounds are -1, +1, +3, +5, and +7. The transition metals have oxidation numbers that may vary from each other in steps of 1. The inner transition elements mostly form oxidation states of + 3, but the first part of the actinoid series acts more like transition elements and the elements have... 

In chloride ions, Cl-, the oxidation number of Cl = -1 (chlorine has been reduced from 0 to -1)... 

Chlorine, in Cl2(aq), at oxidation number 0 has been both oxidised (to +1 in NaCIO) and reduced (to -1 in NaCl). 

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