active metals such as sodium, magnesium, sulphur dioxide (SO2), hydrogen sulphide (H2S)
Examples of oxidation and reduction reactions
Zn is oxidised to ZnO
PbO is reduced to Pb
Mg is oxidised to MgO
H2O is reduced to H2
H2S is oxidised to S
Cl2 is reduced to HCl
REDOX in terms of Electron transfer
1. Oxidation occurs when a reactant loses electron
2. Reduction occurs when a reactant gains electron
In the reaction CuO(s) + Mg(s) → Cu(s) + MgO(s), Magnesium metal loses 2 electrons to form magnesium ions
In the reaction Cu2+ + 2e- → Cu, Copper gains 2 electrons to form copper metal
This is an oxidation reaction
This is a reduction reaction
In the ionic equation CuO(s) + Mg(g) → Cu(s) + MgO(s), the oxidising agent is CuO and the reducing agent is Mg
In the reaction 2Na(s) + Cl2(g) → 2NaCl(s), sodium atom loses 1 electron to form a sodium ion
In the reaction Na+Cl- each molecule of chlorine accepts 2 electrons to form 2 chloride ions
Oxidation occurs when a reactant loses an electron
Reduction occurs when a reactant gains an electron
In this reaction, sodium atom loses 1 electron to form a sodium ion
In this reaction, each molecule of chlorine accepts 2 electrons to form 2 chloride ions
Marginal utility
The additional utility (satisfaction) gained from the consumption of an additional product
If you add up marginal utility for each unit, you get total utility
Oxidation state shows the total number of electrons which have been removed from an element (positive oxidation state) or added to an element (negative oxidation state) to get to its present state
All elemental state has an oxidation number of 0
Potassium in its elemental state has an oxidation number of 0, but when it loses an electron, its oxidation state is +1
Oxidation numbers of various compounds
Fe2O3: +3
CuCl: +1
CuCl2: +2
PbO: +2
PbO2: +4
MnO: +2
Mn2O3: +3
MnO2: +4
Systematic names and traditional names of compounds