Questions about salt hydrolysis??

There are many examples of facilitating hydrolysis. For example, the use of double hydrolysis reaction. For example, in the reaction of aluminum chloride to hydrolysis to aluminum hydroxide, the hydrolysis equation is Al3+ +3H2O = Al(OH)3 + 3H+ Hydrolysis requires endothermy, and heating can make the hydrolysis move forward and move towards the formation of Al(OH)3.

If you want to use alkali to promote hydrolysis, it is more suitable to add ammonia. Ammonia is alkaline, and Al3+ and hydroxide combine to form precipitated aluminum hydroxide, which promotes hydrolysis and positive hydrolysis.

Double-promoting hydrolysis is the use of two hydrolyzed salts to mix, such as carbonate and aluminum ions undergo a violent double-hydrolysis reaction to produce aluminum hydroxide and gas carbon dioxide. Wait a minute.

If Fe3+ is directly dissolved in water first, it is easy to hydrolyze and the following reaction occurs: Fe3++3H2O====Fe(OH)3+3H+, and the resulting solution is turbid and impure. If it is dissolved with concentrated hydrochloric acid first, the hydrolysis of iron ions can be inhibited, so that the hydrolysis equilibrium moves in reverse, effectively avoiding the problem that the obtained is easy to be impure.

Probably not.

I remember that acids and alkalis inhibit the hydrolysis of salts by most of the salts.

The acid is to prevent the hydrolysis of Fe3+ Fe3++3H2O====Fe(OH)3+3H+, and the acid is added to inhibit the hydrolysis, and the equilibrium shifts to the left.

The same principle applies to SN.

For example, the hydrolysis of NH4+ should be combined with OH-, if H+ is added, then the hydrolysis is inhibited, on the contrary, the addition of OH- is to promote hydrolysis (because it reacts with the H+ produced by hydrolysis), of course, it should be in moderation, otherwise it is a reaction.

If you add water first, Fe(Oh)3 will be formed, and the solution will be turbid, and if HCl is added, Fe(Oh)3 will not necessarily dissolve.

1.Greater than. Amount.

2.Amount. 3.Less than.

Rationale:1Let's assume that it is equal to, then the pH < 7, so the ammonia should be a little more, that is, greater than. Ions are conserved, hydroxide and hydrogen ions are equal, and ammonium and chloride ions must also be equal.

2.The magnesium powder reacts completely, does it mean that the consumption is gone?

If yes. It's clearly equal. If this is not the meaning, it is greater than that, on the grounds that the hydrolysis rate is very small.

In the salt hydrolysis equilibrium, why is the more dilute the hydrolysis, the more hydrolysis, and the concentration of ions produced by hydrolysis decreases?

The hydrolysis of salt is in fact promoting the ionization of water. For example, H2O=OH-+H+, S2-+H+=HS-, make the solution alkaline. After adding water, the concentration of water is a fixed value, the concentration of OH- and H+ in the added water is a fixed value, the concentration of H+ in the original solution increases, and the concentration of OH- decreases.

After adding water, the total number of particles in the equilibrium system per unit volume decreases, and the equilibrium should move in the direction of increasing the number of particles, that is, in the direction of ionization, so when the temperature is constant, the smaller the concentration, the greater the degree of ionization, and the salt hydrolysis equilibrium is like this.

According to Le Chatre's principle, the conditions that affect the equilibrium are changed, and the equilibrium shifts in the direction of weakening. Among them, "weakening" is not offsetting, so it can be understood as "the influence of external conditions is greater than the impact of equilibrium movement", adding water is the external condition, and the change in concentration is caused by equilibrium movement, so the concentration decreases after adding water.

Why is "the weaker the acid and base, the more hydrolyzed" in the hydrolysis of chemical salts?

Whether it is an acid or a base, the weaker it is, the more difficult it is to ionize, and the easier it is to form an unionized molecular state.

Why is salt hydrolysis more hydrolyzed the hotter it is?

Salt hydrodesorption heat, according to the principle of Le Chatlet, changes the conditions that affect the equilibrium, and the equilibrium moves in the direction of weakening this change, so it moves in the direction of endothermy, that is, the hotter the more hydrolyzed.

I'm a sophomore in high school, so I have a lot of experience in chemistry, and I may not be very good at it, so forgive me.

What is Hydrolysis of Salts?

Sodium chloride ionized (Na+) and Cl cannot be combined with H+ or OH produced by water ionization, and the aqueous solution C(OH)=C(H+), the solution is neutral. Other strong acids and alkali salts, like sodium chloride, are neutral when dissolved in water.

ch coona + h o (denotes reversible) ch cooh + naoh

Sodium acetate is ionized in water to produce CH COO and (Na+), and CH COO and H+ produced by water ionization (H+ and OH) combine to form a weak electrolyte CH COOH, resulting in C(OH) C(H+). Therefore, weak alkali and strong acid are alkaline when dissolved in water.

NH Cl + H O means reversible) NH H O + HCl

Ammonium chloride ionizes (NH+) and Cl after being dissolved in water, and (NH+) combines with OH produced by water ionization (H+ and OH) to form the weak electrolyte NHHO, resulting in C(H+) C(OH) in solution. Therefore, strong acid and weak alkali salts are acidic when dissolved in water.

In general, if there is a strong acid anion (cation without a strong alkali) in the salt, it is a strong acid and weak alkali salt (acidic).

If a strong alkali cation (anion without a strong acid appears) is a strong alkali, a weak acid (alkaline).

If there is a cation with a strong base and an anion with a strong acid, it is a strong base and a strong acid (neutral).

A salt composed of anions of weak acids such as ammonium carbonate and cations of weak bases.

It will form double hydrolysis to promote hydrolysis.

It should be more comprehensive, haha, give points, give points, and play completely by hand.

The basis of salt hydrolysis is acids and bases.

First of all, you need to understand the acidity and alkalinity of various acids and bases, such as:

Strong acids: hydrochloric acid, sulfuric acid, nitric acid, perchloric acid, etc.

Strong bases: NaOH, KOH, CA(OH)2, etc.

In addition to the strong acid and strong alkali, the rest is weak acid and weak alkali.

Once you understand the acidity and alkalinity, you can understand the hydrolysis problem:

For example: NH4NO3; The salt belongs to a strong acid and weak alkali salt, in the aqueous solution, ammonium ions are hydrolyzed to form ammonia monohydrate and hydrogen ions, and nitrate ions are not hydrolyzed, so the solution is acidic.

The salts that can be hydrolyzed are generally strong acid and weak alkali salts, weak acid and strong alkali salts, and weak acid and weak alkali salts.

...I don't know how to say it, but it's okay to go on the topic.

1. The hydrolysis equation is that the hydrolyzed ions rob the H+ or OH- in the water, not the H+ of the ions in the water, so if H3O+ appears on the right, it is likely to be ionization rather than hydrolysis.

2, F-+H2O=HF+OH-, alkaline.

NH4++H2O=NH3·H2O+H+, acidic non-hydrolyzed Cu2++2H2O=Cu(OH)2+2H+, acidic Clo-+H2O=HCO+OH-, alkaline.

S2-+2H2O=H2S+2OH-, alkaline.

Al3++3H2O=Al(OH)3+3H+, acidic.

Salt ionization of anions and cations in the solution, if the cation can react with water, combined with the OH- ionized by water to form a weak base, it can be hydrolyzed, such as NH4+ + H20 < = > NH3·H20 + H+, cation hydrolysis, the formation of weak base and H+, the hydrolyzed solution is acidic.

If the anion can react with water and combine with H+ ionized by water to form a weak acid, it can be hydrolyzed, such as F- +H20 < = > HF + OH-, the anion is hydrolyzed to generate weak acid and OH-, and the hydrolyzed solution is alkaline.

HCO3)- can both ionize and hydrolyze.

hco3)- h2o < = > h2co3 + oh-

hco3)- h2o < = > co3)2- +h3o+

The previous one, (HCO3)- reacts with water to form its corresponding weak acid, that is, the latter one after hydrolysis, (HCO3)- one less H+, becomes (CO3)2-, that is, ionization hopes that you will figure out the essence of the problem, analyze a few more problems, and write less about it, hoping to make progress.

1 Salt hydrolysis can be regarded as the reverse reaction of acid-base neutralization, salt hydrolysis to obtain the writing of chemical reaction equations Note, hydrolysis is understood as the reaction with water, water is on the side of the reactants, the hydrolysis of multiple weak acids is carried out step by step, and step by step is more difficult than step, most weak base ions are also hydrolyzed step by step, but generally expressed by the total reaction equation. Weakly acidic roots, mixed with a weakly alkaline root solution, may undergo double hydrolysis. The equation follows both the conservation of mass and the conservation of charge.

Generally speaking, strong alkali and weak alkali salts are alkaline, strong acid and weak alkali salts are acidic, strong acid and strong alkali salts are neutral, and weak acid and weak alkali salts depend on their relative size, f-+H2O==HF+OH- (alkaline).

NH4+H2O==acidic).

Sodium sulfate does not have a hydrolysis equation (neutral).

Cu2++H2O===Cu(OH)2+H+(acidic)clo-+H2O===HCO+OH- (alkaline)S2-+H20====HS-+OH- HS-+H2O====H2S+OH- (alkaline).

Al3++H2O==Al(OH)3+H+(acidic) The above reactions are all reversible, because the reactions are very weak, the products are not marked with gas standards or precipitation symbols in Central China.

The stronger the hydrolysis ability, the weaker the acid or base formed by the corresponding acid or alkali root, and the stronger the alkaline or acidic of the corresponding hydrolyzed solution.

Here are a few things to keep in mind:

1. Neutralization is different from neutralization.

Neutralization is a reaction that happens according to the equation, and the resulting salt solution can be neutral, or it may be hydrolyzed to be acidic or basic.

For example, HCl is neutralized with NaOH to form NACL, which is neutral.

HCl is neutralized to produce NH4Cl, which is acidic.

CH3COOH is neutralized with NAOH to form CH3COONA, which is alkaline.

Neutral, on the other hand, is pH=7

2. The concentration of the substance is not the same as the pH.

If the concentration is equal, i.e., the amount and concentration of the substance are equal, i.e., C(NaOH)=C(), then the neutralized HCl is equal.

If the pH is equal, that is, the C(OH-) in the solution is equal at this time, so the concentration is not equal, because it is a weak base, so when C(OH-) is etc., C(>C(NaOH), and the neutralized HCl is not equal. More HCl is neutralized.

If it is neutral after neutralization, then it is not just neutralized, because when it is just neutralized to form NH4Cl, it is acidic, so it needs a little more alkali.

Therefore, it is slightly more to neutralize the same amount of HCl, and if the concentration of alkali is the same, the volume of ammonia is slightly more.

is the same amount of substance in concentration. Because ammonia is a weak electrolyte, ionization produces fewer ions, so it is not as much as NaOH ions.

Ammonia has excess sodium hydroxide because ammonia is a weak electrolyte, so the ammonium chloride produced is acidic, so ammonia must be excessive to ensure the neutrality of the solution.

Ammonia is a weak base that is incompletely ionized into ions.

There are many more that exist in molecular form.

At the same pH, ammonia is much more than sodium hydroxide.

Note: Unable to enter a "reversible sign", replace it with .

For simplification, acetate is denoted as ac-

Regardless of whether the NAAC solution or the NAF solution is a NAAC solution, there are the following three variations:

1) Ionization of salts: Nax = Na+ + X-

2) Acid hydrolysis: X- +H2O Hx + OH-3) Ionization of water: H2O H + OH-

We found that the decrease in X- (acid group) in equation (2) = the increase in OH-, that is, although the degree of hydrolysis of X- is different, the change in anion concentration does not affect the hydrolysis step alone.

However, Eq. 3) is different, the more X-hydrolysis, the more OH- in the solution, the less H+, i.e., from the quantitative point of view, the less OH- is provided in Eq. (3!!

Conclusion: HF is acidic>acetic acid, so NaAC is more hydrolyzed than NAF, and the total anion concentration is smaller.

This kind of question doesn't make much sense, and the college entrance examination can't test such a trivial question. So I know no! It is recommended that you abandon this issue.

Acetic acid has the problem of ionization equilibrium.

Because hydrofluoric acid is weaker acidic than acetic acid... You can look up the ionization constant... Hydrofluoric acid has a much smaller ionization constant than acetic acid...

Therefore, the alkalinity of its acid fluoride ion is stronger than that of acetate... That is, fluoride ions are more easily hydrolyzed (the weaker they are, the more hydrolyzed). The more hydroxide is generated...

Plus the fluoride ions that already existed... The concentration of anions is naturally greater than that of sodium acetate...

This is a test question for salt hydrolysis, the weaker the anion, the greater the degree of hydrolysis, and the smaller the concentration of residual ions. Hydrofluoric acid is more acidic than acetic acid, so the degree of hydrolysis of fluoride ions is less than that of acetate ions, so the concentration of fluoride ions in sodium fluoride solution is greater.