Chemical ionization hydrolysis problem, chemical ionization and hydrolysis

Generally, the acid salts of weak acids can be said to be ionized and hydrolyzed, the ionization of HSO3-, H2PO4- is greater than hydrolysis, and the acid salts of other weak acids are hydrolyzed more than ionized. The college entrance examination is only so much.

You first understand what hydrolysis is and what ionization is.

Hydrolysis is the reaction with water.

You first look at what the product is after hydrolysis, what is the process and what is the process after ionization, such as the hydrolysis process is alkaline, ionized acidic, hydrolysis is stronger than ionization, it means that the solution is alkaline.

When HCO3- and HCN-NaCN are mixed 1:1, the hydrolysis is stronger than that of ionization.

When HSO3-, CH3CoOH-CH3COONA 1:1 and NH3 H2O—NH4Cl are mixed, ionization is stronger than hydrolysis.

These are only within the scope of the college entrance examination, and I will not summarize the rest. If you are interested, you can ask.

As a teacher, it's a joy to answer questions.

The hydrolysis reaction is a dynamic equilibrium process that is influenced by other factors, such as the pH of the water.

Because the ionization of acetic acid is incomplete, the aqueous solution of acetic acid is still acidic, and the concentration of H+ ions in the solution makes the degree of hydrolysis in pure water ineffective"Faint"The hydrolysis reaction of acetate ions moves, so the degree of hydrolysis of acetic acid is weak.

In fact, this and "the degree of ionization of acetic acid is greater than the degree of hydrolysis, so acetic acid is acidic" can be explained by each other, don't dwell on that explain that first, I personally feel that it is a strange circle of chicken or egg first.

Both electrolytes are ionized, strong electrolytes are completely ionized, weak electrolytes are partially ionized, and ions corresponding to weak acids or weak alkali salts are hydrolyzed. The weaker the ionization, the stronger the hydrolysis.

There are too many comparisons of ion concentrations, and the general method is to first determine the condition of the solution, ionization and hydrolysis, and then use it to find a standard and use the equilibrium to judge.

For example, carbonic acid is a weak acid, incomplete ionization, so the carbonate ions in sodium carbonate will be hydrolyzed, if the carbonate is not hydrolyzed, then it should be as much as sodium ions, and now a part of the hydrolysis is less than sodium ions, and the hydroxide generated by hydrolysis is as much as the carbonate consumed, but the hydrolysis is a relatively small part, so the remaining carbonate is more than hydroxide, and the hydrogen ions generated by water ionization are as much as hydroxide, so there are more hydroxide ions than hydrogen ions, and then hydrogen carbonate is completely hydrolyzed from carbonate. And bicarbonate is also hydrolyzed, so it is also less than hydroxide, but hydrogen ions and bicarbonate cannot be compared.

Bicarbonate hydrolysis is greater than ionization is easier to explain, bicarbonate hydrolysis produces hydroxide and ionization produces hydrogen ions, while the solution of sodium bicarbonate is alkaline, i.e., the concentration of hydroxide is higher than that of hydrogen ions, so the hydrolysis process is stronger than ionization.

Hydrolysis of carbonate produces hydroxide, and hydrolysis of bicarbonate also produces hydroxide, but the alkalinity of sodium carbonate solution of the same concentration is stronger than that of sodium bicarbonate, so the hydrolysis of carbonate is stronger than that of bicarbonate, and then the hydrolysis of bicarbonate is stronger than ionization, and it can be seen that the hydrolysis of carbonate is stronger than the ionization of bicarbonate.

Acetic acid and acetate are more complicated, depending on the pH value of acetic acid and sodium acetate solution at the same concentration, or mixing acetic acid and sodium acetate solution with the same molar concentration and volume, the resulting solution is acidic, so the process of ionization of acetic acid to produce hydrogen ions is stronger than the process of hydrolysis of hydroxide from acetate.

Since the hydrolysis of carbonate is stronger than that of ammonium ions, the hydroxide in the ammonium carbonate solution is greater than the hydrogen ions, and the solution is alkaline with a pH greater than 7. However, this does not deduce that the pH value of ammonium bicarbonate is also greater than 7, and it must be known that the hydrolysis of bicarbonate is also stronger than the hydrolysis of ammonium ions.

The strength of ionization and hydrolysis can be judged by comparing the ionization equilibrium constants of weak acids and bases, the higher the constant, the weaker the ionization process, the stronger the hydrolysis process, and vice versa. For example, the two ionization constants of carbonic acid, the first is and the second is, that is, the primary ionization process (carbonic acid ionization into hydrogen ions and hydroxides) is stronger than the secondary (bicarbonate ionization into hydrogen ions and carbonates), and the secondary hydrolysis process (carbonate hydrolysis to hydroxide and bicarbonate) is stronger than the primary (bicarbonate hydrolysis into hydroxide and carbonic acid). The ionization constant of ammonia is smaller than that of both ionization constants of carbonic acid, so it can be seen that the hydrolysis of ammonium ions is weaker than the hydrolysis of carbonate and bicarbonate, so both ammonium carbonate and ammonium bicarbonate are alkaline.

The ionization equilibrium constants of various weak acids and bases can be found in the encyclopedia entry "Ionization equilibrium constants".

Do you want to judge the acidity and alkalinity of a solution based on these laws, or do you want to know the hydrolysis and ionization capacity of an ion?

Your additional question: the second one is so not true, because the hydrolysis of HCO3*- is also greater than the hydrolysis of NH4*+. The hydrolysis of anions is greater than that of cations, which means that the amount of hydroxides produced by anion hydrolysis is greater than the amount of hydrogen ions produced by cation hydrolysis, so the solution is alkaline.

In addition to the few you mentioned, there are more common ones:

HSO3*- Hydrolysis is greater than ionization.

hs*- Hydrolysis is greater than ionization.

S*2- Hydrolysis is greater than ionization.

The hydrolysis of S*2- is greater than that of NH4*+.

The hydrolysis of ammonium is equal to the hydrolysis of acetate.

That's all I can think of so far.

Teacher's answer: The weaker the weak acid, the more difficult it is to ionize, and the stronger the ability of acid ions to bind protons, the easier it is to hydrolyze. You mix ionization with hydrolysis, "there is weakness to hydrolysis, and there is no weakness without hydrolysis; Whoever is weak is hydrolyzed, and who is strong shows whose nature; The weaker the more hydrolyzed, and the weaker are hydrolyzed", such as acetic acid, carbonate and hypochlorous acid, the corresponding degree of hydrolysis of acid ions is weakened in turn.

For the acid salts formed by weak acids, they basically belong to hydrolysis greater than ionization, and they are alkaline in aqueous solution, such as NaHS, NaHCO3; For the acid salt formed by 1:1 of medium and strong acids and bases, it is easy to ionize more than hydrolysis, and it is acidic in aqueous solution, such as NaH2PO4, NaHSO3, NaHC2O3 (sodium hydrogen oxalate).

Strong acid, strong alkali ionization is greater than hydrolysis.

The hydrolysis of one strong and one weak salt is greater than ionization.

The ionization of HSO4-H2PO3-HSO3- in acid salts is greater than that of hydrolysis, and the hydrolysis of others is greater than that of ionization.

Common ionized hydrolysis: bicarbonate, hydrogen thio, monohydrogen phosphate.

Common hydrolytic ionizations: bisulfite, dihydrogen phosphate, hydrogen oxalate.

1.Comparison of the same kind of most acids (bases): ionization hydrolysis (e.g. acetic acid is acidic because it ionizes more than hydrolysis).

Different types of memorization, or judging by acidity and alkalinity. It is acidic, hydrolyzed to form alkali, and ionized to produce acid. Because it is an acid, it is easy to judge that ionization is greater than hydrolysis hydrolysis to form OH, NH4 hydrolysis to produce H, CO3 hydrolysis is greater than NH4 hydrolysis, so OH H, pH 7.

There is also a saying from a high school teacher: The weaker the more hydrolyzed, and whoever is stronger shows his nature. Because HCO3 is very acidic, hydrolysis of HCO3 CO3 yields pH 7.

I just look at how I feel. Memorized several common ones. Questions like NaHS Alkaline and NaHSO3 Acidic and NaH2PO4 Acidic are all explained.

For example, NA2

CO3 is apparently alkaline, CO3 2 - H2O = (reversible) HCO3 - oh- HCO3 - = (reversible) HCO3 - because it is alkaline, the hydrolysis of carbonate is greater than the ionization of bicarbonate.

Question 1: Their concentrations are different, adding hydrochloric acid, acetic acid is generated, which is an acidic solution, so if NaHCO3 is added, will it react? I'm going to assume that it will react, so what do you think is generated?

Acetic acid and sodium carbonate, could these two substances be in one solution? There is a chemical equation that the two of them react and become sodium bicarbonate, so this is impossible, that is, with the addition of NaHCO3, there will be no reaction to generate calculations, which is a mixture of the original two things, and the solution of the two things is alkaline, so the concentration of hydrogen ions is naturally a small rain acidic solution, so it will not be the same, but the concentration of hydrochloric acid is large.

The second question, you will not talk about the previous ones, the upstairs friend method is empiricism, I will provide one.

If you learn conservation very well, then you can use the conservation of charge, and only these four ions in the solution have a positive charge equal to a negative charge.

c(nh4+)+c(h+)=c(cl-)+c(oh-) and because (nh4+) c(cl-), you see, the equation is not automatically c(oh-) c(h+) is it possible? The reason for the solution is complete (NH4+) C(Cl-) is because there is 2mol of NH3 intended to be integrated into the water, and Cl is only 1mol, no matter how you ionize and hydrolyze, you will not be able to be less than Cl, otherwise, everyone will pass less in the future, anyway, there will be more than people, and you can give it to you if you want to prove it strictly, but I am very troublesome to fight, you need to say it again.

I don't know why you're looking for me, how do you know I will?

Oh, and after looking at your analysis again, that C is right, because C(OH) includes the ionization of water, and the ionization of NH4+, which is as much hydrogen as the two of them, and the ammonia in the back is obviously partial, so to add it up, it's right for you to take a look.

Uh- -- The first one, of course, is the high concentration of H+ with HCl. Macroscopically speaking, sodium acetate solution is inherently alkaline. Sodium bicarbonate is also alkaline, so the H+ in the solution with sodium bicarbonate will not be greater than the addition of HCl, microscopically speaking, sodium bicarbonate is mainly hydrolyzed, its ionization is weak, and hydrochloric acid is completely ionized, the H+ concentration difference between the two is several 10 N, so.

You get the idea. The second option c, the concentration of an ion on both sides of the proton conservation is the total concentration of this ion in the solution, so c is right, whether it is water ionization or acid ionization, it is represented by c(h+), d term. Ammonia water and ammonium chloride are mixed in equal volumes, and ammonia is mainly ionized (this teacher should be able to talk about it, there are several typical volumes such as acetic acid and sodium acetate that are also mainly ionized, and hydrolysis is ignored at this time), so the solution is alkaline. So d is right.

CH3COOH solution with pH = 3 and NaOH solution with pH = 11 are mixed in equal volumes, and the two cannot react exactly completely, and acetic acid will be left behind. The so-called "exactly complete reaction" of an acid-base refers to a reaction according to the ratio of the quantities of the substances expressed in the equation.

Ammonium bicarbonate is an acid salt. The aqueous solution of acid salt is not necessarily acidic, for example, NH4HCO3 solution is weakly alkaline, sodium bicarbonate solution is weakly alkaline, and sodium bisulfite solution is weakly acidic.

Because what is generated is not necessarily a strong base or strong salt. Whoever is weak is hydrolyzed, and who is strong shows whose nature;

1. It happens to be completely reacted--- exactly according to the coefficient ratio of the equation.

2. Acid salt. NH4HCO3 is formed by the reaction of 1mol ammonia and 1mol carbonic acid, ammonia is a monobasic base, and carbonic acid is a dibasic acid, and the acid is excessive.

3. Because there is an error in the discoloration range of the acid-base indicator, methyl orange is; Phenolphthalein is 8--10

1 is the reaction to produce sodium acetate, acetic acid and sodium hydroxide have no remaining, C(Na+)>C(CH3Coo-)>C(OH-)>C(H+)

2 Acid salts, cations (volatile electrons) formed during ionization are hydrogen ions in addition to metal ions [or NH4+ (with metal ion properties)], and anions (easily obtained electrons) are salts of acid ions. This is the definition, i.e. after ionization, HCO3- contains H. It should be distinguished from acidic salts.

3 Because the indicator is not exactly 7, and a drop cannot make the pH equal to 7, it is a mutagenesis process.

1. One-to-one reaction ion concentration: Na+>CH3CoO->OH->H+2, acid salt Alkaline salt is one with hydroxide in it.

For example, Cu2(OH)2CO3

3. There is a range of titration endpoints, which are counted in that range, and a little more than half a drop near pH=7 will cause a relatively large change in pH, so generally pH=4-10 seems to be the endpoint.

1. The specific method is to compare the ionization constant and hydrolysis constant of acid ions, the former is acidic, and the latter is alkaline; The ionization constant of bisulfite ions" hydrolysis constant, so the sodium bisulfite solution is acidic.

2. Yes, because they do not react with each other, nor do they react with hydroxide ions.

3. After mixing, it is a mixed solution of sodium acetate and acetic acid of equal concentration, which is acidic, because at this time, the ionization of acetic acid is stronger than the hydrolysis of acetate ions [Note, it is different from 1. This is done by comparing the ionization constant of acetic acid and the hydrolysis constant of acetate ions. Ion concentration sorting is thought of like this:

First of all, according to the acidity of the solution, it is determined that the concentration of hydrogen ions is greater than the concentration of hydroxide ions, and then according to the electric neutrality, it is determined that the concentration of acetate ions is greater than the concentration of sodium ions, and the concentration of acetic acid molecules is considered as follows: because the solution is acidic, only the ionization of acetic acid can be considered, ignoring the hydrolysis of acetate ions, when they are not ionized and hydrolyzed, they are equal concentrations, [also equal to the concentration of sodium ions], and of course ionization will become smaller, so it is smaller than the concentration of acetate ions, and smaller than the concentration of sodium ions, Of course, it is larger than the concentration of hydrogen ions [because hydrogen ions can be seen as formed by ionization of acetic acid, and the ionized ones are much smaller than the rest after all. In this way, the ion concentration ranking result is:

Acetate ion concentration》Sodium ion concentration》Acetic acid molecular concentration》Hydrogen ion concentration》Hydroxide ion concentration.