Acid dissociation steps. Theory of electrolytic dissociation The relationship between the constant and the degree of dissociation

Electrolytic dissociation is the process of breaking down a substance (which is an electrolyte), usually in water, into ions that are free to move.

Acids in aqueous solutions are able to dissociate into positively charged hydrogen ions (H+) and negatively charged acidic residues (for example, Cl - , SO 4 2- , NO 3 -). The former are called cations, the latter anions. The sour taste of solutions of all acids is due precisely to hydrogen ions.

Water molecules are polar. With their negatively charged poles, they attract the hydrogen atoms of the acid to themselves, while other water molecules attract acidic residues to themselves with their positively charged poles. If in the acid molecule the bond between hydrogen and the acid residue is not strong enough, then it breaks, while the electron of the hydrogen atom remains at the acid residue.

In solutions of strong acids, almost all molecules dissociate into ions. In weak acids, dissociation proceeds more weakly, and along with it, the reverse process proceeds - association - when the ions of the acid residue and hydrogen form a bond, and again an electrically neutral acid molecule is obtained. Therefore, in dissociation equations, often for strong acids, an equal sign or a unidirectional arrow is used, and for weak acids, multidirectional arrows, thereby emphasizing that the process goes in both directions.

Strong electrolytes include hydrochloric acid (HCl), sulfuric acid (H 2 SO 4), nitric acid (HNO 3), etc. Weak electrolytes include phosphoric (H 3 PO 4), nitrous (HNO 2), silicon (H 2 SiO 3) and etc.

A monobasic acid molecule (HCl, HNO 3 , HNO 2 , etc.) can only dissociate into one hydrogen ion and one acid residue ion. Thus, their dissociation always proceeds in one step.

Molecules of polybasic acids (H 2 SO 4 , H 3 PO 4 , etc.) can dissociate in several steps. First, one hydrogen ion is split off from them, as a result, a hydro-anion remains (for example, HSO 4 - - hydro-sulfate ion). This is the first stage of dissociation. Further, the second hydrogen ion can be split off, as a result, only the acid residue (SO 4 2-) will remain. This is the second stage of dissociation.

Thus, the number of steps of electrolytic dissociation depends on the basicity of the acid (the number of hydrogen atoms in it).

Dissociation proceeds most easily through the first stage. With each next step, the dissociation decreases. The reason for this is that it is easier to detach a positively charged hydrogen ion from a neutral molecule than from a negatively charged one. After the first stage, the remaining hydrogen ions are more strongly attracted to the acid residue, since it has a greater negative charge.

By analogy with acids, bases also dissociate into ions. In this case, metal cations and hydroxide anions (OH -) are formed. Depending on the number of hydroxide groups in the base molecules, dissociation can also occur in several steps.

The theory of electrolytic dissociation proposed by the Swedish scientist S. Arrhenius in 1887.

Electrolytic dissociation- this is the breakdown of electrolyte molecules with the formation of positively charged (cations) and negatively charged (anions) ions in solution.

For example, acetic acid dissociates like this in an aqueous solution:

CH 3 COOH⇄H + + CH 3 COO - .

Dissociation is a reversible process. But different electrolytes dissociate differently. The degree depends on the nature of the electrolyte, its concentration, the nature of the solvent, external conditions (temperature, pressure).

Degree of dissociation α - the ratio of the number of molecules decomposed into ions to the total number of molecules:

α=v´(x)/v(x).

The degree can vary from 0 to 1 (from the absence of dissociation to its complete completion). Indicated as a percentage. It is determined experimentally. During the dissociation of the electrolyte, the number of particles in the solution increases. The degree of dissociation indicates the strength of the electrolyte.

Distinguish strong And weak electrolytes.

Strong electrolytes- these are electrolytes, the degree of dissociation of which exceeds 30%.

Medium Strength Electrolytes- these are those whose degree of dissociation divides in the range from 3% to 30%.

Weak electrolytes- the degree of dissociation in an aqueous 0.1 M solution is less than 3%.

Examples of weak and strong electrolytes.

Strong electrolytes in dilute solutions completely decompose into ions, i.e. α = 1. But experiments show that dissociation cannot be equal to 1, it has an approximate value, but is not equal to 1. This is not a true dissociation, but an apparent one.

For example, let some connection α = 0.7. Those. according to the Arrhenius theory, 30% of non-dissociated molecules “float” in the solution. And 70% formed free ions. And the electrostatic theory gives a different definition to this concept: if α \u003d 0.7, then all molecules are dissociated into ions, but the ions are only 70% free, and the remaining 30% are bound by electrostatic interactions.

The apparent degree of dissociation.

The degree of dissociation depends not only on the nature of the solvent and solute, but also on the concentration of the solution and temperature.

The dissociation equation can be represented as follows:

AK ⇄ A- + K + .

And the degree of dissociation can be expressed as follows:

With an increase in the concentration of the solution, the degree of dissociation of the electrolyte decreases. Those. the degree value for a particular electrolyte is not a constant value.

Since dissociation is a reversible process, the reaction rate equations can be written as follows:

If dissociation is equilibrium, then the rates are equal and as a result we get equilibrium constant(dissociation constant):

K depends on the nature of the solvent and on the temperature, but does not depend on the concentration of the solutions. It can be seen from the equation that the more non-dissociated molecules, the lower the value of the electrolyte dissociation constant.

Polybasic acids dissociate in steps, and each step has its own value of the dissociation constant.

If a polybasic acid dissociates, then the first proton is most easily split off, and as the charge of the anion increases, the attraction increases, and therefore the proton is split off much more difficult. For example,

The dissociation constants of phosphoric acid at each stage should be very different:

I - stage:

II - stage:

III - stage:

At the first stage, phosphoric acid is an acid of medium strength, and at the 2nd stage it is weak, at the 3rd stage it is very weak.

Examples of equilibrium constants for some electrolyte solutions.

Consider an example:

If metallic copper is added to a solution containing silver ions, then at the moment of equilibrium, the concentration of copper ions should be greater than the concentration of silver.

But the constant has a low value:

AgCl⇄Ag + +Cl - .

Which suggests that by the time equilibrium was reached, very little silver chloride had dissolved.

The concentration of metallic copper and silver are introduced into the equilibrium constant.

Ionic product of water.

The table below contains data:

This constant is called ion product of water, which depends only on temperature. According to dissociation, there is one hydroxide ion for 1 H + ion. In pure water, the concentration of these ions is the same: [ H + ] = [Oh - ].

Hence, [ H + ] = [Oh- ] = = 10-7 mol/l.

If a foreign substance, such as hydrochloric acid, is added to water, the concentration of hydrogen ions will increase, but the ion product of water does not depend on the concentration.

And if you add alkali, then the concentration of ions will increase, and the amount of hydrogen will decrease.

Concentration and are interconnected: the more one value, the less the other.

The acidity of the solution (pH).

The acidity of solutions is usually expressed by the concentration of ions H + . In acidic environments pH<10 -7 моль/л, в нейтральных - pH\u003d 10 -7 mol / l, in alkaline - pH> 10 -7 mol/l.
The acidity of a solution is expressed in terms of the negative logarithm of the concentration of hydrogen ions, calling it pH.

pH = -lg[ H + ].

The relationship between the constant and the degree of dissociation.

Consider an example of the dissociation of acetic acid:

Let's find a constant:

Molar concentration С=1/V, we substitute into the equation and get:

These equations are by the breeding law of W. Ostwald, according to which the dissociation constant of the electrolyte does not depend on the dilution of the solution.

In the dissociation of acids, the role of cations is played by hydrogen ions(H +), no other cations are formed during the dissociation of acids:

HF ↔ H + + F - HNO 3 ↔ H + + NO 3 -

It is hydrogen ions that give acids their characteristic properties: sour taste, red coloring of the indicator, and so on.

Negative ions (anions) split off from an acid molecule are acid residue.

One of the characteristics of the dissociation of acids is their basicity - the number of hydrogen ions contained in an acid molecule that can be formed during dissociation:

• monobasic acids: HCl, HF, HNO 3 ;
• dibasic acids: H 2 SO 4, H 2 CO 3;
• tribasic acids: H 3 PO 4 .

The process of splitting off hydrogen cations in polybasic acids occurs in steps: first one hydrogen ion is split off, then another (third).

Stepwise dissociation of dibasic acid:

H 2 SO 4 ↔ H + + HSO 4 - HSO 4 - ↔ H + + HSO 4 2-

Stepwise dissociation of a tribasic acid:

H 3 PO 4 ↔ H + + H 2 PO 4 - H 2 PO 4 - ↔ H + + HPO 4 2- HPO 4 2- ↔ H + + PO 4 3-

In the dissociation of polybasic acids, the highest degree of dissociation falls on the first stage. For example, when dissociating phosphoric acid, the degree of dissociation of the first stage is 27%; the second - 0.15%; third - 0.005%.

Base dissociation

In the dissociation of bases, the role of anions is played by hydroxide ions(OH -), no other anions are formed during the dissociation of bases:

NaOH ↔ Na + + OH -

The acidity of the base is determined by the number of hydroxide ions formed during the dissociation of one base molecule:

• single acid bases - KOH, NaOH;
• diacid bases - Ca (OH) 2;
• triacid bases - Al (OH) 3.

Polyacid bases dissociate, by analogy with acids, also in steps - at each stage, one hydroxide ion is split off:

Some substances, depending on the conditions, can act both as acids (dissociate with the elimination of hydrogen cations) and as bases (dissociate with the elimination of hydroxide ions). Such substances are called amphoteric(see Acid-base reactions).

Dissociation of Zn(OH) 2 as a base:

Zn(OH) 2 ↔ ZnOH + + OH - ZnOH + ↔ Zn 2+ + OH -

Dissociation of Zn(OH) 2 as acids:

Zn(OH) 2 + 2H 2 O ↔ 2H + + 2-

Salt dissociation

Salts dissociate in water into anions of acid residues and cations of metals (or other compounds).

Salt dissociation classification:

• Normal (medium) salts are obtained by the complete simultaneous replacement of all hydrogen atoms in the acid with metal atoms - these are strong electrolytes, completely dissociate in water with the formation of metal catoins and a single acid residue: NaNO 3, Fe 2 (SO 4) 3, K 3 PO 4.
• Acid salts contain in their composition, in addition to metal atoms and an acid residue, one more (several) hydrogen atoms - they dissociate stepwise with the formation of metal cations, anions of an acid residue and a hydrogen cation: NaHCO 3, KH 2 PO 4, NaH 2 PO 4.
• Basic salts contain in their composition, in addition to metal atoms and an acid residue, one more (several) hydroxyl groups - they dissociate with the formation of metal cations, anions of an acid residue and a hydroxide ion: (CuOH) 2 CO 3, Mg (OH) Cl.
• double salts are obtained by the simultaneous replacement of hydrogen atoms in the acid with atoms of various metals: KAl(SO 4) 2.
• mixed salts dissociate into metal cations and anions of several acid residues: CaClBr.

Normal salt dissociation: K 3 PO 4 ↔ 3K + + PO 4 3- Acid salt dissociation: NaHCO 3 ↔ Na + + HCO 3 - HCO 3 - ↔ H+ + CO 3 2- Basic salt dissociation: Mg(OH)Cl ↔ Mg (OH) + + Cl - Mg(OH) + ↔ Mg 2+ + OH - Double salt dissociation: KAl(SO 4) 2 ↔ K + + Al 3+ + 2SO 4 2- Mixed salt dissociation: CaClBr ↔ Ca 2+ + Cl - + Br -

Aqueous solutions of certain substances are conductors of electric current. These substances are classified as electrolytes. Electrolytes are acids, bases and salts, melts of certain substances.

DEFINITION

The process of decomposition of electrolytes into ions in aqueous solutions and melts under the action of an electric current is called electrolytic dissociation.

Solutions of some substances in water do not conduct electricity. Such substances are called non-electrolytes. These include many organic compounds, such as sugar and alcohols.

Theory of electrolytic dissociation

The theory of electrolytic dissociation was formulated by the Swedish scientist S. Arrhenius (1887). The main provisions of the theory of S. Arrhenius:

- electrolytes, when dissolved in water, decompose (dissociate) into positively and negatively charged ions;

- under the action of an electric current, positively charged ions move towards the cathode (cations), and negatively charged ones move towards the anode (anions);

— dissociation is a reversible process

KA ↔ K + + A −

The mechanism of electrolytic dissociation consists in the ion-dipole interaction between ions and water dipoles (Fig. 1).

Rice. 1. Electrolytic dissociation of sodium chloride solution

Substances with an ionic bond dissociate most easily. Similarly, dissociation occurs in molecules formed according to the type of polar covalent bond (the nature of the interaction is dipole-dipole).

Dissociation of acids, bases, salts

During the dissociation of acids, hydrogen ions (H +), or rather, hydronium ions (H 3 O +), are always formed, which are responsible for the properties of acids (sour taste, action of indicators, interaction with bases, etc.).

HNO 3 ↔ H + + NO 3 -

During the dissociation of bases, hydrogen hydroxide ions (OH -) are always formed, which are responsible for the properties of bases (discoloration of indicators, interaction with acids, etc.).

NaOH ↔ Na + + OH −

Salts are electrolytes, during the dissociation of which metal cations (or ammonium cation NH 4 +) and anions of acid residues are formed.

CaCl 2 ↔ Ca 2+ + 2Cl -

Polybasic acids and bases dissociate in steps.

H 2 SO 4 ↔ H + + HSO 4 - (I stage)

HSO 4 − ↔ H + + SO 4 2- (stage II)

Ca (OH) 2 ↔ + + OH - (I stage)

+ ↔ Ca 2+ + OH -

Degree of dissociation

Among electrolytes, weak and strong solutions are distinguished. To characterize this measure, there is the concept and magnitude of the degree of dissociation (). The degree of dissociation is the ratio of the number of molecules dissociated into ions to the total number of molecules. often expressed in %.

Weak electrolytes include substances in which, in a decimolar solution (0.1 mol / l), the degree of dissociation is less than 3%. Strong electrolytes include substances in which, in a decimolar solution (0.1 mol / l), the degree of dissociation is more than 3%. Solutions of strong electrolytes do not contain undissociated molecules, and the process of association (association) leads to the formation of hydrated ions and ion pairs.

The degree of dissociation is particularly influenced by the nature of the solvent, the nature of the solute, temperature (for strong electrolytes, with increasing temperature, the degree of dissociation decreases, and for weak electrolytes, it passes through a maximum in the temperature range of 60 o C), concentration of solutions, introduction of ions of the same name into the solution.

Amphoteric electrolytes

There are electrolytes that, upon dissociation, form both H + and OH - ions. Such electrolytes are called amphoteric, for example: Be (OH) 2, Zn (OH) 2, Sn (OH) 2, Al (OH) 3, Cr (OH) 3, etc.

H + +RO − ↔ ROH ↔ R + + OH −

Ionic reaction equations

Reactions in aqueous electrolyte solutions are reactions between ions - ionic reactions, which are written using ionic equations in molecular, full ionic and reduced ionic forms. For example:

BaCl 2 + Na 2 SO 4 = BaSO 4 ↓ + 2NaCl (molecular form)

Ba 2+ + 2 Cl − + 2 Na+ + SO 4 2- = BaSO 4 ↓ + 2 Na + + 2 Cl− (full ionic form)

Ba 2+ + SO 4 2- = BaSO 4 ↓ (abbreviated ionic form)

pH value

Water is a weak electrolyte, so the dissociation process proceeds to a small extent.

H 2 O ↔ H + + OH -

The law of mass action can be applied to any equilibrium and the expression for the equilibrium constant can be written:

K = /

The equilibrium concentration of water is a constant value, therefore.

K = = KW

The acidity (basicity) of an aqueous solution is conveniently expressed in terms of the decimal logarithm of the molar concentration of hydrogen ions, taken with the opposite sign. This value is called the pH value (pH).

USE. Electrolytic dissociation of salts, acids, alkalis. Ion exchange reactions. Salt hydrolysis
Solutions and their concentration, disperse systems, electrolytic dissociation, hydrolysis

At the lesson you will be able to test your knowledge on the topic “Unified State Examination. Electrolytic dissociation of salts, acids, alkalis. Ion exchange reactions. Salt hydrolysis. You will consider solving problems from the Unified State Exam of groups A, B and C on various topics: "Solutions and their concentrations", "Electrolytic dissociation", "Ion exchange reactions and hydrolysis". To solve these problems, in addition to knowing the topics under consideration, you also need to be able to use the table of solubility of substances, know the electron balance method and have an idea about the reversibility and irreversibility of reactions.

Topic: Solutions and their concentration, disperse systems, electrolytic dissociation

Lesson: USE. Electrolytic dissociation of salts, acids, alkalis. Ion exchange reactions. Salt hydrolysis

I. Choosing one correct option out of 4 offered.

Question	A comment
A1. Strong electrolytes are:	By definition, strong electrolytes are substances that completely decompose into ions in an aqueous solution. CO 2 and O 2 cannot be strong electrolytes. H 2 S is a weak electrolyte. Correct answer 4.
A2. Substances that dissociate only into metal ions and hydroxide ions are: 1. acids 2. alkalis 4. amphoteric hydroxides	By definition, a compound that, when dissociated in an aqueous solution, forms only hydroxide anions is called a base. Only alkali and amphoteric hydroxide are suitable for this definition. But in the question it sounds that the compound should dissociate only into metal cations and hydroxide anions. Amphoteric hydroxide dissociates in steps, and therefore hydroxometal ions are in solution. Correct answer 2.
A3. The exchange reaction proceeds to the end with the formation of a water-insoluble substance between: 1. NaOH and MgCl 2 2. NaCl and CuSO 4 3. CaCO 3 and HCl (solution)	To answer, you need to write these equations and look in the solubility table to see if there are insoluble substances among the products. This is in the first reaction magnesium hydroxide Mg (OH) 2 Correct answer 1.
A4. The sum of all coefficients in full and reduced ionic form in the reaction betweenFe(NO 3 ) 2 +2 NaOHis equal to:	Fe(NO 3) 2 +2NaOH Fe(OH) 2 ↓ +2Na NO 3 molecular Fe 2+ +2NO 3 - +2Na+2OH - Fe(OH) 2 ↓ +2Na + +2 NO 3 - complete ionic equation, the sum of the coefficients is 12 Fe 2+ + 2OH - Fe(OH) 2 ↓ abbreviated ionic, the sum of the coefficients is 4 Correct answer 4.
A5. The abbreviated ionic reaction equation H + + OH - → H 2 O corresponds to the interaction: 2. NaOH (Р-Р) + HNO 3 3. Cu(OH) 2 + HCl 4. CuO + H 2 SO 4	This abbreviated equation reflects the interaction between a strong base and a strong acid. The base is available in 2 and 3 options, but Cu (OH) 2 is an insoluble base Correct answer 2.
A6. The ion exchange reaction proceeds to completion when the solutions are drained: 1. sodium nitrate and potassium sulfate 2. potassium sulfate and hydrochloric acid 3. calcium chloride and silver nitrate 4. sodium sulfate and potassium chloride	Let us write how the ion exchange reactions between each pair of substances would take place. NaNO 3 + K 2 SO 4 →Na 2 SO 4 + KNO 3 K 2 SO 4 + HCl → H 2 SO 4 + KCl CaCl 2 +2AgNO 3 → 2AgCl↓ + Ca(NO 3) 2 Na 2 SO 4 + KCl → K 2 SO 4 + NaCl According to the solubility table, we see that AgCl↓ Correct answer 3.
A7. In an aqueous solution, it dissociates stepwise:	Polybasic acids undergo stepwise dissociation in an aqueous solution. Among these substances, only H 2 S is an acid. Correct answer 3.
A8. Reaction equation CuCl 2 +2 KOH→ Cu(Oh) 2 ↓+2 KClcorresponds to the abbreviated ionic equation: 1. СuCl 2 + 2OH - → Cu 2+ + 2OH - + 2Cl - 2. Сu 2+ +KOH→Cu(OH) 2 ↓+K + 3. Cl - +K + →KCl 4. Сu 2+ +2OH - →Cu(OH) 2 ↓	Let's write the full ionic equation: Cu 2+ + 2Cl - + 2K + + 2OH - → Cu (OH) 2 ↓ + 2K + + 2Cl - We exclude unbound ions, we get the reduced ionic equation Сu 2+ +2OH - →Cu(OH) 2 ↓ Correct answer 4.
A9. The reaction goes almost to completion: 1. Na 2 SO 4 + KCl→ 2. H 2 SO 4 + BaCl 2 → 3. KNO 3 + NaOH → 4. Na 2 SO 4 + CuCl 2 →	Let's write hypothetical ion exchange reactions: Na 2 SO 4 + KCl → K 2 SO 4 + Na Cl H 2 SO 4 + BaCl 2 → BaSO 4 ↓ + 2HCl KNO 3 + NaOH → NaNO 3 + KOH Na 2 SO 4 + CuCl 2 → CuSO 4 + 2NaCl According to the solubility table, we see BaSO 4 ↓ Correct answer 2.
A10. A solution has a neutral environment: 2. (NH 4) 2 SO 4	Only aqueous solutions of salts formed by a strong base and a strong acid have a neutral environment. NaNO3 is a salt formed by the strong base NaOH and the strong acid HNO3. Correct answer 1.
A11. The acidity of the soil can be increased by introducing a solution:	It is necessary to determine which salt will give an acid reaction of the medium. It must be a salt formed by a strong acid and weak base. This is NH 4 NO 3. Correct answer 1.
A12. Hydrolysis occurs when dissolved in water:	Only salts formed by a strong base and a strong acid do not undergo hydrolysis. All of the above salts contain anions of strong acids. Only AlCl 3 contains a weak base cation. Correct answer 4.
A 13. Does not undergo hydrolysis: 1. acetic acid 2. acetic acid ethyl ester 3. starch	We have hydrolysis great importance V organic chemistry. Esters, starch and protein undergo hydrolysis. Correct answer 1.
A14. What number denotes a fragment of the molecular equation chemical reaction, corresponding to the multiple ionic equation C u 2+ +2 Oh - → Cu(Oh) 2 ↓? 1. Cu(OH) 2 + HCl → 2. CuCO 3 + H 2 SO 4 → 3. CuO + HNO 3 → 4. CuSO4 +KOH→	According to the reduced equation, it follows that you need to take any soluble compound containing a copper ion and a hydroxide ion. Of all the above copper compounds, only CuSO 4 is soluble, and only in the aqueous reaction is there OH -. Correct answer 4.
A15.Which substances react to produce sulfur oxide?: 1. Na 2 SO 3 and HCl 2. AgNO 3 and K 2 SO 4 3. BaCO 3 and HNO 3 4. Na 2 S and HCl	In the first reaction, an unstable acid H 2 SO 3 is obtained, which decomposes into water and sulfur oxide (IV) Correct answer1.

II. Tasks with a short answer and matching.

IN 1. The total sum of all the coefficients in the full and abbreviated ionic equation for the reaction between silver nitrate and sodium hydroxide is ...	Let's write the reaction equation: 2AgNO 3 +2NaOH→Ag 2 O↓+ 2NaNO 3 +H 2 O Full ionic equation: 2Ag + +2NO 3 - +2Na + +2OH - →Ag 2 O↓+ 2Na + +2NO 3 - +H 2 O Abbreviated ionic equation: 2Ag + +2OH - →Ag 2 O↓+H 2 O Correct answer: 20
AT 2. Make a complete ionic equation for the interaction of 1 mol of potassium hydroxide with 1 mol of aluminum hydroxide. Enter the number of ions in the equation.	KOH + Al(OH) 3 ↓→ K Full ionic equation: K + +OH - + Al(OH) 3 ↓ → K + + - Correct answer: 4 ions.
AT 3. Establish a correspondence between the name of the salt and its relation to hydrolysis: A) ammonium acetate 1. does not hydrolyze B) barium sulfide 2. by cation C) ammonium sulfide 3. by anion D) sodium carbonate 4. by cation and anion	To answer the question, you need to analyze what strength the base and acid formed these salts. Correct answer A4 B3 C4 D3
AT 4. A solution of one mole of sodium sulfate contains 6.02sodium ions. Calculate the degree of dissociation of the salt.	Let's write the equation for the electrolytic dissociation of sodium sulfate: Na 2 SO 4 ↔ 2Na + + SO 4 2- Decomposed into ions 0.5 mol of sodium sulfate.
AT 5. Establish a correspondence between reagents and abbreviated ionic equations: 1. Ca (OH) 2 + HCl → A) NH 4 + + OH - → NH 3 + H 2 O 2. NH 4 Cl + NaOH → B) Al 3+ + OH - → Al (OH) 3 ↓ 3. AlCl 3 +KOH → B) H + +OH - →H 2 O 4. BaCl 2 + Na 2 SO 4 → D) Ba 2+ + SO 4 2- → BaSO 4 ↓ Correct answer: C1 A2 B3 D4
AT 6. Write the complete ionic equation corresponding to the reduced one: WITHO 3 2- +2 H + → CO 2 + H 2 O. Specify the sum of the coefficients in the molecular and full ionic equations.	You need to take any soluble carbonate and any soluble strong acid. Molecular: Na 2 CO 3 + 2HCl → CO 2 + H 2 O + 2NaCl; The sum of the coefficients is 7 Full ionic: 2Na + + CO 3 2- + 2H + + 2Cl - → CO 2 + H 2 O + 2Na + + 2Cl -; The sum of the coefficients is 13

III.Assignments with a detailed answer

Question