Know the strength of the oxidation or reduction of two chemicals, and how to judge whether they can

If we only know the simple oxidation or reduction, we cannot judge all reactions, because for example, metathesis reactions are not redox reactions.

If the redox reaction can be judged according to oxidation and reduction, there are some rules.

For example, nitric acid can undergo redox reaction with copper, so in general, the oxidation of acidic KMno4 solution is greater than that of nitric acid, so it can be concluded that acidic KMno4 can undergo redox reaction with copper.

The main thing is to deepen the understanding of matter based on the accumulation of ordinary times, and judge according to certain experiences.

Of course, in the end, it depends on Gibbs's free energy.

Personal opinion.

When I was in junior high school, I didn't remember the strength and weakness of the redox properties of several chemicals.

The periodic table actually covers many, many things, a deep understanding.

The main group of metal elements is strengthened from top to bottom.

Non-metallic main group elements, oxidized from top to bottom.

I didn't use it for a long time and forgot. Hehe.

But that's right, I hope it helps.

In chemistry, you are understanding and thinking slowly.

I don't think it should be possible to judge whether it can react just by looking at the strength of oxidative reduction! From a purely personal point of view, I don't want to pretend to understand this kind of academic question, after all, I am also a student.

If the element is at its valence, then it is oxidizing; On the contrary, if it is at a negative price, it is reductive. However, the strength of oxidation or reduction is not directly related to the valency of the element, not the higher the valence, the stronger the oxidation, the strength is only related to the difficulty of gaining and losing electrons, the easier it is to obtain electrons, the stronger the oxidation, the more volatile the electrons are reducible, and the number of electrons gained and lost has nothing to do with the number of electrons gained and lost. For example, in chlorine compounds, the oxidation of HClL is stronger than that of HCl4

Generally, if you want to judge whether a substance is a strong oxidizing agent or a strong reducing agent, you can only remember the common substances. For example, common oxidants include halogen element, O, KMno4, K2Cr2O7, concentrated H2SO4, concentrated dilute HNO3, Na2O2, Fe3+, MNO2 and so on. Common reducing agents are S2-, I-, Br-, H2S, SO2 and sulfite, Fe2+

Method induction:

The comparison of the oxidation and reduction of substances is essentially a comparison of the difficulty of gaining and losing electrons of substances. That is, the easier it is for a substance to get electrons, the stronger its oxidation, and the more difficult it is to get electrons, the weaker its oxidation; Conversely, the more likely a substance is to lose electrons, the stronger its reducibility, and the more difficult it is to lose electrons, the weaker its reducibility.

One. Using valency to compare the strength of oxidation and reduction of substances.

The strength of oxidation and reduction of different valence substances formed by the same element: the lowest valence state of the element only has oxidation, the lowest valence state of the element only has reduction, and the intermediate valence state of the element has both oxidation and reduction.

Such as: substances composed of iron, oxidizing: ; Reducibility:.

Two. Using the different activity of the elements, the strength of the oxidation and reduction of substances is compared.

1.For metals, the more reactive the metal (the stronger the metallicity), the stronger the reduction of its elemental matter, and the weaker the oxidation of its metal cation.

For example, for the order table of metal activity: k, ca, na, mg, al, zn, fe, sn, pb(h), cu, hg, ag, pt, au, their activity (metallicity) decreases sequentially; Elemental reducibility:

k>ca>na>mg>al>hg>ag>pt>au；Oxidation of ions:.

2.For non-metals, the more active the non-metals (the stronger the non-metallic properties), the stronger the oxidation of their non-metallic elements, and the weaker the reducing properties of their anions.

For example, for the general non-metallic activity order: f, cl, br, i, s, its liveliness (its metallicness) decreases sequentially; Oxidation of its elemental elements:; The reducibility of its anions:.

The liveliness (non-metallicness) of Si, P, S and Cl increased sequentially. Its elemental oxidation: SICU.

Hello! Generally speaking, active metal elements (potassium, calcium, sodium, magnesium, aluminum, zinc, iron, tin, lead, hydrogen) are reducible, while strong acids and alkalis are oxidizing. The strength of the redox property of the substance can also be seen from the chemical reaction, the displacement reaction loses protons to gain electrons is the reducing agent, and the protons are obtained and lose electrons are oxidants.

If hydrogen is obtained or replaced, then it is oxidation.

1. The oxidation or reduction of elemental or simple ions can be judged according to the similarity and degeneration of the periodic table.

For example, Br2 should have strong oxidizing properties similar to Cl2 (similarity), but weaker oxidation (degrading) than Cl2, and stronger reduction than Cl-.

2. According to the specific chemical equation:

Oxidation: Oxidizing agent" oxidation product.

Reducibility: Reducing agent" reducing product.

3. According to the electrode reaction and the sequence of discharge.

The reducibility of the anode material is stronger than that of the cathode material.

The oxidation (or reduction) of the first discharge is strong.

By judging the redox properties of the corresponding ions. If the ionic oxidation is strong, the oxidation of the element is weak. The same is true for reductivity. When it is difficult to judge whether two substances are, observe whether a displacement reaction can occur, so as to make a judgment.

Look at the reaction equation ... The reducing agent is greater than the reducing product, and the oxidant is greater than the oxidation product.

It is judged according to the valence state of the element.

Substances with elements at ** are generally oxidizing, substances with elements at low valences are generally reducing, and when the elements are in the intermediate valence state, the substance is both oxidizing and reducing. For the same element, generally the higher the valence state, the stronger its oxidation; The lower the valence, the more reductive it is. Such as oxidation:

fe3+＞fe2+，s(+6)＞s(+4)＞s(0)

Redox reaction is the process by which "strong" becomes "weak". In other words, it is the process by which a strong reducing agent reacts with a strong oxidant to form a weak oxidant (oxidation product) and a weak reducing agent (reducing product).

Oxidation: Cl2 > Br2 > I2

Reducibility: cl-

Therefore, Cl2 can oxidize both Br- and I-; Br2 can only oxidize I-, not Cl-.

It does not need to be compared with sodium.

As long as it is better than chlorine and bromine.

They are elements of the same main group, according to the periodic table order, chlorine is on top, cl2 is highly oxidizing, so chloride ion reduction is weaker than bromine.

OK?