Comparison of particle concentrations in Na2CO3 and NaHCO3 solutions 30

It was inconvenient to write, so I replaced it with a codename. where Na2CO3 is denoted as 1 and NaHCO3 is denoted as 2.

H ions, while the primary hydrolysis capacity of 2 is weaker than that of secondary hydrolysis, and the ability to ionize H is weaker.

2. OH ion: 1>2, it is the same as H

The concentration of the ions is just the opposite, because of these H

Both ions and oh ions come from the ionization of water, so H is more. oh

Necessarily less. 3. Na: 1>2, because Na is not hydrolyzed and ionized, just look at it directly according to the mol ratio, there are two mol in 1, and there is only one mol in 2.

4. CO3: 1》2, because 1 hydrolysis ionization is very weak, so there is a large amount of CO3 and a very small amount of HCO3 due to hydrolysis in 1, while there is a large amount of HCO3 and a very small amount of CO3 due to ionization in 2.

5. HCO3:1 "2, the reason is the same as above.

6. H2CO3 (carbonic acid): 1<2, because 2 is easier to hydrolyze to produce H2CO3, and 1 needs to be hydrolyzed twice to produce H2CO3, which is more troublesome than 2.

It mainly depends on what kind of properties it presents, which is generally the case, and the main aspect of the analysis is the hydrolysis situation, which you can refer to.

Comparison of particle concentrations in Na+ >CO32- >OH- >HCO3- >H2CO3 > H+NaHCO3 solution:

na+ >hco3- >oh- >h2co3 > co32- >h+

1) Comparison of particle concentration in Na2CO3 solution:

Comparison of particle concentrations in Na+ >CO32- >OH- >HCO3- >H2CO3 > H+2)NaHCO3 solution:

na+ >hco3- >oh- >h2co3 > co32- >h+

In the NaHSO3 solution, there is a presence of HSO3.

Ionization equilibrium: HSO3 = H+ +SO32 Hydrolysis equilibrium: HSO3 +H2O = H2SO3 + OH Since NaHSO3 is an acidic solution, it is ionized hydrolyzed.

So [H2O] [Na+] Hso3-] H+] So32-] Oh-] H2SO3].

NaHCO3 is basic.

HCO3 is present.

Hydrolytic equilibrium: HCO3 + H2O = H2CO3 + OH Ionization equilibrium: HCO3 = H+ +CO32 Since NaHCO3 is an alkaline solution, it is hydrolyzed ionized.

So [Na+]>HCO3-]>OH-]>H2CO3]>[H+]>CO32-].

Na2CO3 is ionized first in solution: Na2CO3 = 2Na+ +CO32-

At the same time, there is an equilibrium in the solution: H2O = H+ +OH- (1) CO32- +H+ = HCO3- (hydrolyzed essence of carbonate) (2) (1) step moves less than step (2), for the ionization process of water, because CO32- binds H+ (regarded as an external condition) to reduce the H+ concentration, that is, the external conditions reduce the H+ concentration, according to Le Chartri's principle, although the ionization equilibrium of water moves positively, it only weakens, and cannot change this decreasing trend, That is to say, the H+ that is bound by step (2) is greater than that produced when the equilibrium is moved in the positive direction of (1) after that, and the decrease in C(H+)=C(HCO3-) in step (2) is C(HCO3-)>C(H+).

HCO3- in Na2CO3 solution.

Primary hydrolysis yields HCO3-

CO32- +H2O = HCO3- +OH- hydrolysis constant kh = KW Ka2

2、h2co3

Primary ionization yields HCO3-

h2co3 = hco3 - h+

The ionization constant ka1 =

3. Compare KH1 and KA1

The results showed that the primary hydrolysis of sodium carbonate was greater than that of the primary ionization of carbonate, and although there were also secondary hydrolysis and secondary ionization, the primary level was the main factor due to the homoionic effect. So, the HCO3- in the Na2CO3 solution.

c(na+)>c(hco3-)>c(oh-)>c(h+)>c(co32-)

First of all, the strong electrolyte ionized Na+ and HCO3- are the largest, and due to the hydrolysis of HCO3, they decrease somewhat, so C(Na+) > C(HCO3-).

Secondly, due to the alkalinity of the solution, the degree of hydrolysis of HCO3 is greater than that of ionization, and due to the ionization of water, C(OH-)>C(H+)>C(CO32-).

Let the concentration of NaHCO3 in the solution be A

Because the salt NaHCO3 is completely dissolved in solution and the sodium ions are completely dissociated, the concentration of sodium ions is also A;

Carbonic acid is a weak acid and is partially dissociated in two steps, where the dissociation constant K1 = * 10 -7, K2 = * 10 -11, and the dissociation of HCO3- is the secondary dissociation of carbonic acid, so the concentration of hydrogen ions and the concentration of carbonate ions are both axk2;

The concentration of undissociated HCO3- is A-AXK2.

c(na⁺)>c(hco₃⁻)c(co₃²⁻c(oh⁻)>c(h⁺)

According to the ionization equation and the ion equation of hydrolysis, it can be seen that the order of the concentration of ions in sodium carbonate solution from large to small is: c(na)>c(co(oh)>c(hco)c(h)c(h)).

Bicarbonate ions are both ionized and hydrolyzed, and the hydrolysis tendency is greater than the ionization tendency, so it can be seen that the concentration of each ion is in the order of C(Na)>C(HCO)C(OH)>C(CO(H)

When the amount and concentration of Na Co and NaHCO are mixed, because the carbonic acid is weak according to ion hydrolysis, bicarbonate ion hydrolysis and ionization, the first hydrolysis of carbonate is greater than the second step hydrolysis, and the bicarbonate ion hydrolysis trend is greater than the ionization tendency, so the solution C (HCO) C (Co

In summary, the order of the concentration of each ion in the mixed solution is: C(Na)>C(HCO)C(COc(OH)>C(H).

Sodium carbonate is a strong electrolyte that is completely ionized, and the equation for ionization is:

na2co3=2na^++co3^2-

Carbonate ion hydrolysis is step-by-step, and hydrolysis is weak. The first hydrolysis is greater than the second hydrolysis. The ionic equation for hydrolysis is:

co3^2-++h2o﹤=﹥hco3^-+oh^-

hco3^-+h2o﹤=﹥h2co3+oh^-

According to the ionization equation and the ion equation of hydrolysis, it can be seen that the order of the concentration of each ion in sodium carbonate solution from large to small is:

c(na^+)c(co3^2-)>c(oh^-)c(hco3^-)c(h^+)

Sodium bicarbonate is a strong electrolyte that is completely ionized, and the equation for ionization is:

nahco3=na^++hco3^-

The ionic equation for the hydrolysis of bicarbonate ions is:

hco3^-+h2o﹤=﹥h2co3+oh^-

The bicarbonate ionization equation is.

hco3^-﹤=﹥h^+ co3^2-

Bicarbonate ions are both ionized and hydrolyzed, and the hydrolysis tendency is greater than the ionization tendency, so it can be seen that the concentration of each ion is in the order from large to small: C(Na +)C(HCO3 -)C(OH -)C(CO3 2-)>C(H+).

When the amount and concentration of Na2CO3 and NaHCO3 are mixed, because the carbonic acid is weak according to ion hydrolysis, bicarbonate ion hydrolysis and ionization, the first hydrolysis of carbonate is greater than the second step hydrolysis, and the hydrolysis trend of bicarbonate ions is greater than the tendency of ionization, so the solution of C(HCO3-)C(CO32-).

In summary, the order of the concentration of each ion in the mixed solution is:

c(na^+)c(hco3^-)c(co3^2-)>c(oh^-)c(h^+)

na+>hco3->co32->oh->h+..CO3 hydrolysis to produce solution is alkaline, so hydrolysis is the main, CO32- hydrolysis to reduce it and can produce HCO3-, so HCO3->CO32-, and hydrolysis is very weak, alkaline after mixing, so OH->H+.

Upstairs has to remember PH and KB, are you tired? Now that you know the size, what do you want to compare? Do you want to look up books during exams?

The weaker the acid base, the more OH- ions are hydrolyzed by the salt, the greater the alkalinity, and the greater the pH value.

CH3COOH can react with NA2CO3 NACLO NAHCo3, and CH3COOH is the strongest according to the principle of strong acid to weak acid.

Because CO2 reacts with Naclo, H2CO3 is more acidic than HCl.

And because HCo cannot produce CO2 with Na2CO3, HCO3 cannot react with NaHCO3, HCO3->HCO3

Na2CO3 is more basic than NaHCO3 because Na2CO3 is hydrolyzed twice.

So acidic CH3COOH>H2CO3>HCO3->HCl

So basic Na2CO3> Naclo> NaHCO3>CH3Coona

The special one here is Na2CO3 because it is hydrolyzed twice.

Ionization constant of CH3COOH.

The ionization constant of HClO is 3 10-8

h2co3 k1= k2=

Acidity: The weaker the acidity of CH3CoOH H2CO3 HCO3-, the stronger the hydrolysis ability and the higher the pH value of the solution.

pH from large to small Na2Co3 Naclo NaHCO3 CH3Coona

KB= of ch3coona

KB1= of Na2CO3

kb = of naclo

KB2 = of NaHCO3

When the amount and concentration of substances are the same, the larger the hydrolysis constant, the greater the pH value, and the pH value of all the above four substances is ranked in order from large to small:

na2co3 >naclo> nahco3>ch3coona

The weaker it is, the more hydrolyzed. So ph: naclo> na2co3 > nahco3>ch3coona

Because of the acidity: CH3COOH>H2CO3>HCl

So the ions go from weak to strong: clo->CO32-> HCO3->CH3COO-

pH from large to smallNa2CO3 NaHCO3 CH3COONA NACLO

Strong bases and weak salts are the same as sodium hydroxide, acidic HClo ch3cooh HCO3-H2CO3

So there will be the above results.

Do you want to be specific about the pH range, or just the size?

According to the acidity of these several alkali conjugated acids:

ch3cooh h2co3 hclo hco3-available salt solution ph: na2co3 naclo nahco3 ch3coona

1: Add CaCl2 solution to the two solutions, NaHCO3 does not react with CaCl2, while Na2CO3 reacts with CaCl2 to form CaCO3 solution.

2. Add dilute HCl dropwise to the two solutionsWhen dilute HCl is added dropwise in Na2CO3 solution, only a small amount of gas is generated, and even no gas is released. If dilute HCl is added dropwise in NaHCO3, gas (in large quantities) is immediately released.

Three: add agno3, no precipitate is nahco3, and there is precipitate na2co3

Four: Add BaCl2, there is a precipitate is Na2CO3There is no precipitate of NaHCO3

Five: Two put into water, the solubility of NaHCO3 is not very good, and Na2CO3 is better.

Six: with pH test paper, the alkalinity of sodium carbonate is greater than that of sodium bicarbonate, the pH value is large is Na2CO3, and the small is NaHCO3

Seven: prepare a solution of the same concentration (quality), evaporate at constant temperature and reduced pressure under the same conditions, and the first to precipitate the crystal is NaHCO3

Eight: sodium carbonate and hydrochloric acid reaction is mainly exothermic, and you can feel the heat of the test tube. Sodium bicarbonate reacts with hydrochloric acid, which is mainly endothermic, and you can feel that the test tube is a little cold.

9. Carbonate will react with positive 2-valent magnesium ions to form carbonate precipitate.

10: Phenol is used to identify, phenol reacts with sodium carbonate to produce sodium bicarbonate.