Solving Some Reaction Equations in High School Chemistry!!

Strong acid means that acid dissolved in water can ionize into hydrogen ions and acid ions to a large extent, and weak acid is relative to strong acid, which refers to the partial ionization of acid in solution, and most of it exists in a molecular state in solution. The general acid-to-acid reaction is actually a metathesis reaction, and whether this reaction can occur depends on the strength of the acid but also considers whether there is precipitation, gas, and the formation of high or low boiling point acids.

For example, phosphoric acid (a moderately strong acid) is used to produce Hi and HBR (both of which are stronger acids than hydrochloric acid). Although phosphoric acid is a weak acid, the reaction can occur due to the formation of gas.

For example, perchloric acid is formed by the reaction of sulfuric acid with barium perchlorate, although we say that perchloric acid is more acidic than sulfuric acid, but because of the formation of barium sulfate precipitation, the reaction can also occur.

Therefore, we should understand it for strong acid to make weak acid, and do not simply classify it as strong acid to make weak acid when there is an acid and salt that reacts with salt to form another acid and salt.

It is not necessary to make a strong acid to make a weak acid, there are special circumstances: such as: H2S Cuso4 H2SO4 Cus

This reaction mainly produces a substance that is insoluble in strong acids (i.e., insoluble substances in ionic reactions).

There are two scenarios for weak acids to make strong acids:

1) Metathesis reaction of non-redox reactions.

As mentioned by the upstairs man, a more acidic acid can produce a weaker acid, because the ionization degree of the stronger acid in the aqueous solution is greater than that of the weaker acid, and the hydrogen ions produced by ionization can combine with the acid root ions of the weaker acid, forming weaker acid molecules that are more difficult to ionize and "free" out of the system, resulting in the chemical equilibrium shifting in the direction of the formation of weaker acids.

In fact, the reason why weak acids can produce strong acids is the same, that is, the whole reaction proceeds in the direction of decreasing the total ion concentration, but because the solubility of the resulting salts is really small.

For example: CuSO4 + H2S == Cus (precipitation) + H2SO4 and so on.

2) Redox reactions.

This is purely related to the redox size of the reactants and products. The law of redox reaction occurs: oxidizing agent with strong oxidation + reducing agent with strong reducing agent == oxidizing product with weak oxidation + reducing product with weak reduction.

For example: Cl2 + H2S == S (precipitate) + 2HCl

H2SO3 + Cl2 == H2SO4 + HCl (untrimmed) and so on.

Na2CO3 + H2S = NaHCO3 + Nahs strong acid to weak acid, strong alkali to weak alkali, that is, the alkalinity of sodium carbonate is stronger than sodium bicarbonate and sodium hydrothiodide, and the acidity of hydrogen sulfide is greater than that of sodium hydrosulfide and sodium bicarbonate, H2S and carbonic acid are very close, and carbonic acid cannot be prepared, so it can only stay at the point of acid salt.

Just like using carbon dioxide to pass into sodium sulfide, the result is the same, CO2 + H2O + Na2S = NaHCO3 + NaHS

Many chemical reactions are also related to the order of titration, such as the reaction formula of hydrochloric acid added to sodium carbonate and sodium carbonate added to hydrochloric acid is different

This type of reaction mainly includes the following:

na2co3 + 2 mhso4 == na2so4 + mso4 + h2o +co2

where m represents the metallic element).

The essence of the reaction is the following ionic reactions:

CO3 2- +2 H+ == H2O + CO2 Since bisulfate is completely ionized by H+ in aqueous solution, it can be approximated as a strong acid, which will be more convenient for high school problem solving...

I remember that there was a order of strength: potassium, sodium, calcium (hydrogen), zinc, iron, copper.

CO2 and NaS will no longer form sodium sulfide precipitates.

It is a strong acid to a weak acid, nitric acid and a compound of sulfuric acid. CO3 carbonic acid. Silicic acid..

When sodium carbonate reacts with hydrogen sulfide, sodium carbonate is alkaline and hydrogen sulfide is acidic, and the two undergo a centering reaction to obtain sodium bicarbonate and sodium hydrosulfide. No carbon dioxide gas will be obtained because the acidity of the two is very close.

Here we first give the correct equation: (S2O3)2- +4Cl2 + 5H2O = 2(SO4)2- +8Cl- +10H+

Next, analyze the reason for your mistake, in fact, the reaction equation you mentioned is possible, but the premise is that the chlorine gas is insufficient, because the question gives a sufficient amount of chlorine, so it can be shown that these amounts of chlorine gas convert the +2 valence s in sodium thiosulfate into +6 valence s, so it is not difficult to imagine that the right side should be sulfate, chloride ions, hydrogen ions, and then trim.

Here's a little advice I have for you to study chemistry in the future, and that's how I used to do it! You must pay attention to details in learning chemistry, and some key words and key sentences in the topic may be the turning point or breakthrough point of the whole topic, and you should pay more attention to it in the future connection, I believe that this will make your chemistry level have a qualitative leap!

The product should be SO42-, chlorine is very oxidizing, SO3- is highly reducible, and it is impossible not to be oxidized, so the chemical equation: S2O32-+4Cl2+5H2O=2SO42-+8Cl-+10H+

Cl2 has strong oxidizing properties, and the product cannot be sulfite, it should be sulfate.

Cl2 has strong oxidizing properties and oxidizes sulfites to sulfates in sufficient amounts.

Cl2 has strong oxidizing properties to oxidize sulfites to sulfates, and the gains and losses of electrons in redox reaction must be equal.

The sulphurous acid is also oxidized by chlorine to sulphuric acid.

Damn, you're sleeping in class, your chemistry teacher saw it, and I can't beat you, I don't believe your teacher didn't talk about it.

Sufficient chlorine ions are introduced into the Na2S2O3 solution

s2o3(2-) 4cl2 + 5h2o == 2so4(2-) 8cl- +10h+

Hello, Bonus: 1, 2, 4, 6, 9, 11, 12, 13, 17, 22 Aggregate: 5 Replace: 3, 14, 15, 20, 21, , 23, 26 Elimination: 7, 8, 10

Oxidation, 16, 18

Reduce: 1, 2, 17, 22

Hydrolysis: 21 Acid base: 19, 24, 25

Hope it helps!

If you don't understand, please ask! Hope!

How to say it, the exam will not be biased, just memorize the basics.

Uncommon? Are you sure you're right?

gas) 8h2o

The catalyst is potassium permanganate.

2Fe3+ +Fe = 3Fe2+ , so in the end you definitely don't get +3 valence iron ions. So a answer is wrong, the correct one is: 3fe + 8h+ +3NO3 - 3FE2+ +3NO +4H2OB answer, add excess clarified lime water, indicating that there will be a large amount of Ca2+ in the final solution, so there can be no CO3 2- remaining in the end, because:

ca2+ +co3 2- =caco3↓。So B answer is wrong, the correct one is: Ca2+ +HCO3- +OH- =CaCO3 +H2O C answer, we know that aluminum ions can be precipitated with hydroxide ions to obtain aluminum hydroxide, and aluminum hydroxide will be soluble in a strong alkali solution, but because ammonia is only a weak base, its ionized hydroxide ions are not enough to dissolve aluminum hydroxide, so C is wrong, the correct is:

Al3+ +3NH3·H2O=AL(OH)3 +3NH4+, so after excluding the answer, D is correct, is there any doubt? I hope I can help you and wish you progress in your studies.

A is wrong. The excess iron reaction should produce ferrous ions. B is wrong, because the lime water is excessive, so the remaining CO32- ions can continue to combine with the Ca2+ in the lime water to precipitate CaCO3.

C is false, because Al(OH)3 can only be dissolved in solutions with strong acids or bases, then since ammonia is a weak base, it can only produce Al(OH) regardless of whether there is an excess of ammonia or not. So the answer is D

This question tests the judgment of the true and false of the ion equation, pay attention: excessive, small amount, appropriate amount of words. Then, we also have to look at the conservation of charge, the conservation of atoms.

Conditional light.

Condition ignition. Conditional catalysts.

Conditional catalysts.

Condition benzene) + Hno3 C6H5-NO2 + H2O condition heating, benzene is best written as a structural formula, because it is not easy to write on the Internet, so it is not written.

benzene) + br2 c6h5br + hbr

Because the generated HBR is not obvious, so there is no need to carry a gas symbol, because many reactions are related to temperature and the amount of matter, so some reactions are not unique, I only wrote the main one, if there is a mistake, please understand, for the sake of hard work, right!

light) ch3cl

br2__ch2brch2br.

3O2 (ignited) 2CO2

h2o__ch3ch2oh.

o2_(cu)_2ch3cho

2na__2c3h7ona

hno3_(h2so4)_c6h5no2

br2_(febr2)_c6h5br

HBR should be that, and there may be something wrong.