Identify redox reactions by changes in oxidation number using: (a) the oxidation number of elements in their uncombined state is zero (b) the oxidation number of a monatomic ion is the same as the charge on the ion (c) the sum of the oxidation numbers in a compound is zero (d) the sum of the oxidation numbers in an ion is equal to the charge on the ion

State the sources of the sulfur dioxide (burning sulfur or roasting sulfide ores) and oxygen (air) in the Contact process

Describe tests to identify the gases: (a) ammonia, ( NH_3 ), using damp red litmus paper (b) carbon dioxide, ( CO_2 ), using limewater (c) chlorine, ( Cl_2 ), using damp litmus paper (d) hydrogen, ( H_2 ), using a lighted splint (e) oxygen, ( O_2 ), using a glowing splint (f) sulfur dioxide, ( SO_2 ), using acidified aqueous potassium manganate(VII)