Redox

Question 1

What is the oxidation number of any uncombined element? Give examples.

Answer 1

The oxidation number of any uncombined element is 0.
E.g H2, O2, K, S8, Fe

Question 2

What is the oxidation number of combined oxygen? Give examples.

Answer 2

The oxidation number of combined oxygen is -2.
E.g H2O, CaO, CO2

Question 3

What is the oxidation number of combined hydrogen? Give examples.

Answer 3

The oxidation number of combined hydrogen is +1.
E.g H2SO4, HCl

Question 4

What is the oxidation number of a simple ion? Give examples.

Answer 4

The oxidation number of a simple ion is the charge on the ion.
E.g H+, Mg2+, F-

Question 5

What is the oxidation number of combined Fluorine?

Answer 5

The oxidation number of combined fluorine is -1.

Question 6

Give an example of an exception to the oxidation number rule of combined oxygen.

Answer 6

H2O2, the oxygen has a -1 oxidation number.

Question 7

Give two examples of an exception to the oxidation rule of combined hydrogen.

Answer 7

NaH and CaH2, the hydrogen has a -1 oxidation.

Question 8

What is the oxidation number of transition elements? Give examples.

Answer 8

The oxidation number matches the roman numerals.
E.g Fe (II) oxidation is +2, Fe (III) oxidation is +3

Question 9

Oxidation in terms of electron transfer is:

Answer 9

The loss of electrons (e-)

Question 10

Reduction in terms of electron transfer is:

Answer 10

The gain of electrons (e-)

Question 11

Oxidation in terms of oxidation number is:

Answer 11

An increase in oxidation number.

Question 12

Reduction in terms of oxidation number is:

Answer 12

A decrease in oxidation number.

Question 13

Redox is when:

Answer 13

Reduction and oxidation take place.

Question 14

An oxidising agent is:

Answer 14

An electron acceptor, the one that is reduced acts as the oxidising agent.

Question 15

A reducing agent is:

Answer 15

An electron donor, the one that is oxidised acts as the reducing agent.