In the high valence substance is generally oxidizing.
Such as:
some non-elemental: O2, part of Cl2
metal cations: Fe3 +, MnO4-(Mn7 +).
In a low valence substance is generally reducing. Such as
:
part of the single mass of metal: Cu of Ag
part of the non-metal anions: Br-, the I-and so on. The
oxidation resistance, the judge
of reducing the strength of the judgment
(a) according to the chemical equation (1) oxidant (oxidized) + reductant (reducing) === reduction products + oxidation products < BR> oxidants ---- Restore products
the electron valence lower, be restored, the occurrence of the reaction
reductant --- loss of electronic oxidation products
increased valence is oxidized, the oxidation of oxidative resistance
: oxidants> oxidation products
reductive: reductant> Restore the product
(2) to determine the
oxidation: oxidant according to the same reaction of the oxidant, the reductant the reductant
restore nature: reducing agent> the oxidant
(b) according to substances active order
for metal reductant (1), elemental metal, reducing the strength of general and metal activity consistent with the order, that is located behind the metal, less likely to lose the e-reduction of the weaker.
Reductive: K> Ca> Na> Mg> Al> Mn> Zn> Cr> Fe> Ni> Sn> Pb> (H)> Cu> Hg> Ag> Pt> Au
(2) metal cation oxidation the order
K +
the F --- of Cl --- Br --- I --- S
(c), according to the reaction conditions Difficult to judge. The more likely response, strong oxidants.
Such as: 16HCl (concentrated) +2 of KMnO4 == 2KCl +2 of MnCl2 +8 H2O +5 of Cl2 (gas)
4HCl (thick) + MnO2 === (heating) of MnCl2 +2 H2O + Cl2 (gas)
4HCl (thick) + O2 == (heating, CuCl2 catalyst) 2H2O +2 of Cl2 (gas)
the oxidation: of KMnO4> MnO2 was> of O2
(d) according to the valence level of oxidation products to determine
when containing variable price elements reductant under similar conditions in different oxidant, to judge according to the oxidation product of the valence state level of oxidants, strong or weak. Such as:
2Fe +3 of Cl2 == (lit) 2FeCl3
Fe + S to == (heating) of FeS
oxidation: of Cl2> S-
(5) based on the periodic table to determine
( 1) with the main group elements (from top to bottom)
non-metallic atoms (or elemental) oxidation gradually decreased, the corresponding anion reducing gradually increased. The
metal atoms reducing gradually increased world pie network information , and the corresponding cation oxidation is gradually weakened
the (2) gradually weakened with the cycle of main group elements (from left to right)
elemental reducing oxidation gradually enhanced
cation oxidation gradually increased anion reduction gradually decreased.
Acidic
(6) the elements of the highest price oxide hydrates, acid-base strength of the stronger, the corresponding elements of oxidizing the stronger the stronger
alkaline, the corresponding elements of the stronger
two different metal composition of the original battery terminals. The anode metal electronic outflow pole, the cathode metal electronic flow into the pole.
Restore: anode metal> Cathode metal
for (8) according to the concentration of a substance the size of judgment
oxidizing (or reducing) the greater the concentration, the oxidation (or restore) the stronger, and vice versa, the weaker.
(9) the judge
element valence valence state level of general price change only oxidizing elements in the highest valence state, in the lowest state only to restore, in the central parity states, both oxidizing And the reduction. Generally at their highest valence state, the most oxidizing, with the lower valence, oxidation weakened restore enhancements.
Sodium borohydride to restore a similar product: Na, H2,World Steel Pipe , of CO, C and so on.