Oxidation Numbers
Important Questions on Oxidation Numbers
When reacts with hydrazine, , nitrogen gas is evolved.
Explain, using oxidation numbers, why moles of react with moles of ?

When reacts with hydrazine, , nitrogen gas is evolved.
Deduce the oxidation number change for each nitrogen atom when is converted to .

When reacts with hydrazine, , nitrogen gas is evolved.
Deduce the oxidation number change of the bromine atom when is converted to .

The compound decomposes when heated:
State the oxidation number of bromine in .

The compound decomposes when heated:
State the oxidation number of bromine in .

When a salt containing iodide ions is warmed with concentrated sulphuric acid and , iodine is evolved:
Deduce the oxidation number of in the ion.

Iodine, , reacts with thiosulphate ions , to form iodide ions, , and tetrathionate ions, as . State the oxidation number of each sulphur atom in a ion.

Iodine, , reacts with thiosulphate ions , to form iodide ions, , and tetrathionate ions, as . State the oxidation number of each sulphur atom in a ion.

Aluminium reacts with hydrochloric acid to form aluminium chloride, , and hydrogen. This is a redox reaction. Deduce the change in oxidation number when a hydrogen ion turns into a hydrogen atom.

The unbalanced equation for the reaction of sulphur dioxide with bromine is as shown below:
State the change in oxidation number for each bromine atom.

The unbalanced equation for the reaction of sulphur dioxide with bromine is as shown below:
State the change in oxidation number for each atom.

The unbalanced equation for the reaction of sulphur dioxide with bromine is as shown below:
State the oxidation number of bromine in .

The unbalanced equation for the reaction of sulphur dioxide with bromine is as shown below:
State the oxidation number of bromine in .

The unbalanced equation for the reaction of sulphur dioxide with bromine is as shown below:
State the oxidation number of sulphur in .

The unbalanced equation for the reaction of sulphur dioxide with bromine is as shown below:
State the oxidation number of sulphur in .

Calcium reacts with cold water to form calcium hydroxide, , and hydrogen, . State the oxidation number of hydrogen in hydrogen gas.

Calcium reacts with cold water to form calcium hydroxide, , and hydrogen, . State the oxidation number of hydrogen in water.

State the oxidation number of calcium in calcium hydroxide.

Calcium reacts with cold water to form calcium hydroxide, , and hydrogen, . State the oxidation number of calcium in calcium metal.

Look at the equation: . Which one of these statements about the oxidation number changes is correct?

