Redox & Disproportionation Reactions

Question 1

Oxidation is the

what of oxygen

what of hydrogen

what of oxidation state

what of electrons

Answer 1

Oxidation is the gain of oxygen, eg:
Cu + H2O → CuO + H2
(Cu has gained an oxygen and is oxidised)

Oxidation is also the loss of hydrogen, eg:
2NH3 + 3Br2 → N2 + 6HBr
(NH3 has lost hydrogen and is oxidised

Oxidation is also the loss of electrons, eg:
Cu2+ + Mg → Mg2+ + Cu

Oxidation causes an increase in oxidaiton state, eg:
Cu2+ + Mg → Mg2+ + Cu

Question 2

reduction is the

what of oxygen

what of hydrogen

what of oxidation state

what of electrons

Answer 2

Reduction is the loss of oxygen, eg:
Cu+ H2O → 2CuO + H2
(H2O has been reduced)

Reduction is also the gain of hydrogen, eg:
2NH3+ 3Br2 → N2 + 6HBr
(Br has been reduced)

Reduction causes a decrease in oxidation number, eg:
Cu2+ + Mg → Mg2+ + Cu

(the change in oxidation state of Cu is -2 thus Cu is reduced)

reduction is also the gain of electrons, eg:
Cu2+ + Mg → Mg2+ + Cu
(Cu has been reduced)

Question 3

Redox reactions are reactions in which

Answer 3

Redox reactions are reactions in which oxidation and reduction take place simultaneously
While one species is oxidising, another is reducing in the same reaction, eg:
Cu2++ Mg → Mg2+ + Cu

(Cu has been reduced and Mg has been oxidised)

Question 4

A disproportionation reaction is a reaction in which

Answer 4

the same species is both oxidised and reduced

Question 5

step 1 of disproportionation reaction

Answer 5

Write the unbalanced equation and identify the atoms that change in oxidation state:

Question 6

step 2 of disproportionation reaction

Answer 6

Deduce the oxidation state changes

Question 7

step 3 of disproportionation reaction

Answer 7

Balance the oxidation state changes:

Question 8

step 4 of disproportionation reaction

Answer 8

Balance the charges

Question 9

step 5 of disproportionation reaction

Answer 9

Balance the atoms