This process is known as anionic hydrolysis. The burning sensation associated with heartburn is a result of the acid of the stomach leaking through the muscular valve at the top of the stomach into the lower reaches of the esophagus. The dissociation chemical reaction is: NH4Cl(solid) = NH4+(aqueous) + Cl-(aqueous). The concentration of hydrogen ions is calculated as: As the value of Ka = NH4Cl is 5.6 X 10-10 at 25C, Also, we are calculating the hydrogen ion concentration for 1 M NH4Cl solution. Find Net Ionic equation for hydrolysis , Expression for equilibrium Hint: We will probably need to convert pOH to pH or find [H3O+] using [OH] in the final stages of this problem. The value of Ka for this acid is not listed in Table E1, but we can determine it from the value of Kb for aniline, C6H5NH2, which is given as 4.6 1010 : \[\mathrm{\mathit{K}_a(for\:C_6H_5NH_3^+)\mathit{K}_b(for\:C_6H_5NH_2)=\mathit{K}_w=1.010^{14}} \nonumber \], \[\mathrm{\mathit{K}_a(for\:C_6H_5NH_3^+)=\dfrac{\mathit{K}_w}{\mathit{K}_b(for\:C_6H_5NH_2)}=\dfrac{1.010^{14}}{4.610^{10}}=2.310^{5}} \nonumber \]. The vegetable, such as a cucumber, is placed in a sealed jar submerged in a brine solution. Legal. acid and base. As discussed earlier, the combination of strong acid and weak base results in the formation of an acidic salt. (d) The NH4+NH4+ ion is acidic (see above discussion) and the F ion is basic (conjugate base of the weak acid HF). Why is an aqueous solution of NH4Cl Acidic? When we mix solutions of an acid and a base, an acid-base neutralization reaction occurs. The aluminum hydroxide tends to cause constipation, and some antacids use aluminum hydroxide in concert with magnesium hydroxide to balance the side effects of the two substances. Likewise, some salts contain a single ion that is amphiprotic, and so the relative strengths of this ions acid and base character will determine its effect on solution pH. Strong acids may also be hydrolyzed. Bronsted-Lowry theory: A molecule that readily gives away protons in an aqueous solution is an acid while the molecule that takes up those protons, given away by another molecule, is a base. (b) The Na+ cation is inert and will not affect the pH of the solution; while the HCO3HCO3 anion is amphiprotic. This allows for immediate feedback and clarification . The crystals are formed as a result of the gaseous eruption, however, they do not last long as they are soluble in water. 6 Milk of Magnesia is a suspension of the sparingly soluble base magnesium hydroxide, Mg(OH)2. not only neutralizes stomach acid, it also produces CO2(g), which may result in a satisfying belch. Hydrolysis reactions break bonds and release energy. A solution of this salt contains ammonium ions and chloride ions. Hydrolysis reactions occur when organic compounds react with water. 2.3: Relative Strengths of Acids and Bases, Example \(\PageIndex{1}\): pH of a Solution of a Salt of a Weak Base and a Strong Acid, Example \(\PageIndex{2}\): Equilibrium of a Salt of a Weak Acid and a Strong Base, Equilibrium in a Solution of a Salt of a Weak Acid and a Weak Base, Example \(\PageIndex{3}\): Determining the Acidic or Basic Nature of Salts, Example \(\PageIndex{4}\): Hydrolysis of [Al(H2O)6]3+, status page at https://status.libretexts.org, Predict whether a salt solution will be acidic, basic, or neutral, Calculate the concentrations of the various species in a salt solution, Describe the process that causes solutions of certain metal ions to be acidic, A strong acid and a strong base, such as HCl(. The word neutralization seems to imply that a stoichiometrically equivalent solution of an acid and a base would be neutral. The characteristic properties of aqueous solutions of Brnsted-Lowry acids are due to the presence of hydronium ions; those of aqueous solutions of Brnsted-Lowry bases are due to the presence of hydroxide ions. Consequently, the bonded water molecules' OH bonds are more polar than in nonbonded water molecules, making the bonded molecules more prone to donation of a hydrogen ion: The conjugate base produced by this process contains five other bonded water molecules capable of acting as acids, and so the sequential or step-wise transfer of protons is possible as depicted in few equations below: This is an example of a polyprotic acid, the topic of discussion in a later section of this chapter. One way to ensure that math tasks are clear is to have students work in pairs or small groups to complete the task. 12th Chemistry EngMed QueBank MSCERT | PDF | Crystal Structure | Chlorine As a salt acquires its pH based upon the acidic or basic strength of its constituent compounds, NH4Cl is acidic. Potassium carbonate (K2CO3) is a white salt, soluble in water (insoluble in ethanol) which forms a strongly alkaline solution. The second column is blank. A weak acid and a strong base yield a weakly basic solution. The aluminum ion is an example. Aqueous Solutions of Salts - Chemistry LibreTexts Solve for x and the equilibrium concentrations. The second column has the header of A l ( H subscript 2 O ) subscript 6 superscript 3 positive sign plus H subscript 2 O equilibrium arrow H subscript 3 O superscript positive sign plus A l ( H subscript 2 O ) subscript 5 ( O H ) superscript 2 positive sign. Under the second column is a subgroup of four columns and three rows. Answer: Hydrolysis usually is a equilibrated reaction between ion from weak bases or acids and water. , As you may have guessed, antacids are bases. We determine Kb as follows: \[K_\ce{b}=\ce{\dfrac{[CH3CO2H][OH- ]}{[CH3CO2- ]}}=5.610^{10} \nonumber \], \[=\dfrac{[\ce{CH3CO2H}](2.510^{6})}{(0.050)}=5.610^{10} \nonumber \]. 2 Module 7 Buffer Preparation and Hydrolysis of Salts I. For a reaction between sodium phosphate and strontium nitrate write out the following: This page titled 2.4: Hydrolysis of Salt Solutions is shared under a CC BY license and was authored, remixed, and/or curated by OpenStax. In Leclanch cells, the aqueous solution of ammonium chloride was used as an electrolyte. However, in this case, the hydrated aluminum ion is a weak acid (Figure \(\PageIndex{2}\)) and donates a proton to a water molecule. Solved Can anyone help me with these calculations? If you - Chegg (If this occurs in other solvents, it will be called 'solvolysis' or just the name of solvent plus -lysis such as ethanolysis.) H 44) What are the products of hydrolysis of NH4Cl? A strong acid and a weak base yield a weakly acidic solution, not because of the strong acid involved, but because of the conjugate acid of the weak base. This is similar to the simplification of the formula of the hydronium ion, H3O+ to H+. The fourth column has the following: 0, x, x. However, even if we mix stoichiometrically equivalent quantities, we may find that the resulting solution is not neutral. The lining of the esophagus is not protected from the corrosive effects of stomach acid the way the lining of the stomach is, and the results can be very painful. When we neutralize a weak base with a strong acid, the product is a salt containing the conjugate acid of the weak base. They are characterized by the splitting of a water molecule into a hydrogen and a hydroxide group with one or both of these becoming attached to an organic starting product. However, it is not difficult to determine Ka for \(\ce{NH4+}\) from the value of the ionization constant of water, Kw, and Kb, the ionization constant of its conjugate base, NH3, using the following relationship: \[K_\ce{w}=K_\ce{a}K_\ce{b} \nonumber \]. $\ce{NH4+}$ ions being the conjugate acid of a weak base is strong and reacts with $\ce{H2O}$ to give $\ce{H+}$ thus making the solution acidic. The arithmetic checks; when 1.2 103 M is substituted for x, the result = Ka. The acidic or basic nature of salt is determined by the strength of the acid and base that combine to form that salt. Example 2.4. Cooking is essentially synthetic chemistry that happens to be safe to eat. H are licensed under a, Measurement Uncertainty, Accuracy, and Precision, Mathematical Treatment of Measurement Results, Determining Empirical and Molecular Formulas, Electronic Structure and Periodic Properties of Elements, Electronic Structure of Atoms (Electron Configurations), Periodic Variations in Element Properties, Relating Pressure, Volume, Amount, and Temperature: The Ideal Gas Law, Stoichiometry of Gaseous Substances, Mixtures, and Reactions, Shifting Equilibria: Le Chteliers Principle, The Second and Third Laws of Thermodynamics, Representative Metals, Metalloids, and Nonmetals, Occurrence and Preparation of the Representative Metals, Structure and General Properties of the Metalloids, Structure and General Properties of the Nonmetals, Occurrence, Preparation, and Compounds of Hydrogen, Occurrence, Preparation, and Properties of Carbonates, Occurrence, Preparation, and Properties of Nitrogen, Occurrence, Preparation, and Properties of Phosphorus, Occurrence, Preparation, and Compounds of Oxygen, Occurrence, Preparation, and Properties of Sulfur, Occurrence, Preparation, and Properties of Halogens, Occurrence, Preparation, and Properties of the Noble Gases, Transition Metals and Coordination Chemistry, Occurrence, Preparation, and Properties of Transition Metals and Their Compounds, Coordination Chemistry of Transition Metals, Spectroscopic and Magnetic Properties of Coordination Compounds, Aldehydes, Ketones, Carboxylic Acids, and Esters, Composition of Commercial Acids and Bases, Standard Thermodynamic Properties for Selected Substances, Standard Electrode (Half-Cell) Potentials, Half-Lives for Several Radioactive Isotopes. Because acetic acid is a weak acid, its Ka is measurable and Kb > 0 (acetate ion is a weak base). EMMY NOMINATIONS 2022: Outstanding Limited Or Anthology Series, EMMY NOMINATIONS 2022: Outstanding Lead Actress In A Comedy Series, EMMY NOMINATIONS 2022: Outstanding Supporting Actor In A Comedy Series, EMMY NOMINATIONS 2022: Outstanding Lead Actress In A Limited Or Anthology Series Or Movie, EMMY NOMINATIONS 2022: Outstanding Lead Actor In A Limited Or Anthology Series Or Movie. NH3 + H+D. After this ammonium chloride is separated, washed, and dried from the precipitate. A byproduct of the pickling process changes the flavor of the vegetables with the acid making them taste sour. NH4Cl is ammonium chloride. The OpenStax name, OpenStax logo, OpenStax book covers, OpenStax CNX name, and OpenStax CNX logo The chloride ion has no effect on the acidity of the solution since HCl is a strong acid. When you dissolve ammonium chloride crystals in water (H2O), the ammonium chloride compound decomposes into its component ions: NH4+ and Cl-. When we have heartburn, it feels better if we reduce the excess acid in the esophagus by taking an antacid. The new step in this example is to determine Ka for the \(\ce{C6H5NH3+}\) ion. Lastly, the reaction of a strong acid with a strong base gives neutral salts. Hydrolysis involves the reaction of an organic chemical with water to form two or more new substances and usually means the cleavage of chemical bonds by the addition of water. The chloride ion is the conjugate base of hydrochloric acid, and so its base ionization (or base hydrolysis) reaction is represented by Since HCl is a strong acid, Ka is immeasurably large and Kb 0 (chloride ions don't undergo appreciable hydrolysis). The first column has the following: 0.10 (which appears in red), negative x, 0.10 minus x. 2 But this pH dependent reaction yields different products. NH4OH + HClE. The sodium ion has no effect on the acidity of the solution. KAl(SO4)2. ----- NH4Cl. The aluminum ion is an example. The acetate ion, THe ammonium is acting as an acid (proton donor) hence the ammonia (NH3) is the conjugate base of the acid (ammonium). In the case of NH4Cl the dissociation equation can be written as: Here, the NH4Cl hydrolysis to form an NH4+ ion, which is the conjugate acid of ammonia, while the Cl- ion which is the conjugate base of ammonia. A weak acid plus a weak base can yield either an acidic, basic, or neutral solution. 3 In a solution of a salt formed by the reaction of a weak acid and a weak base, to predict the pH, we must know both the Ka of the weak acid and the Kb of the weak base. The second column has the header of A l ( H subscript 2 O ) subscript 6 superscript 3 positive sign plus H subscript 2 O equilibrium arrow H subscript 3 O superscript positive sign plus A l ( H subscript 2 O ) subscript 5 ( O H ) superscript 2 positive sign. Under the second column is a subgroup of four columns and three rows. When we neutralize a weak acid with a strong base, we get a salt that contains the conjugate base of the weak acid. In a solution of a salt formed by the reaction of a weak acid and a weak base, to predict the pH, we must know both the Ka of the weak acid and the Kb of the weak base. The value of Kb can be calculated from the value of the ionization constant of water, Kw, and Ka, the ionization constant of the conjugate acid of the anion using the equation: For the acetate ion and its conjugate acid we have: \[\mathrm{\mathit{K}_b(for\:\ce{CH_3CO_2^-})=\dfrac{\mathit{K}_w}{\mathit{K}_a(for\:CH_3CO_2H)}=\dfrac{1.010^{14}}{1.810^{5}}=5.610^{10}} \nonumber \]. Explanation : Hydrolysis is reverse of neutralization. But NH4OH molecule formed ionises only partially as shown above. then you must include on every physical page the following attribution: If you are redistributing all or part of this book in a digital format, Thus hydrolysis adds water to break down, whereas condensation builds up by removing water. 6 Solving this equation we get [CH3CO2H] = 1.1 105 M. What is the pH of a 0.083-M solution of CN? What is the approximately pH of a 0.1M solution of the salt. In a solution of a salt formed by the reaction of a weak acid and a weak base, to predict the pH, we must know both the Ka of the weak acid and the Kb of the weak base. The equilibrium equation for this reaction is simply the ionization constant. Calculating the pH for 1 M NH4Cl Solution. The \(\ce{C6H5NH3+}\) ion is the conjugate acid of a weak base. Determine the acetic acid concentration in a solution with \(\ce{[CH3CO2- ]}=0.050\:M\) and [OH] = 2.5 106 M at equilibrium. As shown in Figure 14.13, the K a of NH 4 + = 5.65 x 10 10.. Some salts formed in neutralization reactions may make the product solutions slightly acidic or slightly basic. This is the most complex of the four types of reactions. C) NH3 + H3O+ + Cl- DUHOXHCL E) NH3 + OH- + HCI 49) Which diagram best represents the products when equimolar amounts of HF (g) and NH3 (g) react? Write formula equations and net ionic equations for the hydrolysis of sodium carbonate in water. The conjugate acid of the strong base is a weaker acid than water and has no effect on the acidity of the resulting solution. Is NH4Cl an acid or base? Strong vs Weak - Ammonium chloride - Topblogtenz It is odorless with a density of 1.519 gm/cm3, It has a pH value between 4.5 and 6 and its pKa value is 9.24. The lactic acid eventually increases the acidity of the brine to a level that kills any harmful bacteria, which require a basic environment. A weak acid produces a strong conjugate base. 11 Uses of Platinum Laboratory, Commercial, and Miscellaneous, CH3Br Lewis Structure, Geometry, Hybridization, and Polarity. For example, ammonium chloride, NH4Cl, is a salt formed by the reaction of the weak base ammonia with the strong acid HCl: \[\ce{NH3}(aq)+\ce{HCl}(aq)\ce{NH4Cl}(aq) \nonumber \]. It is defined as the fraction (or percentage) of the total salt which is hydrolysed at equilibrium. Ammonium chloride in water is acidic and it produces ammonia, H+ ions, Cl- ions and H2O. We will not find a value of Ka for the ammonium ion in Table E1. For both types of salts, a comparison of the Ka and Kb values allows prediction of the solutions acid-base status, as illustrated in the following example exercise. Use 4.9 1010 as Ka for HCN. Required fields are marked *. 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Substituting the available values into the Kb expression gives. When we neutralize a weak acid with a strong base, we get a salt that contains the conjugate base of the weak acid. Ammonium Chloride (NH4Cl) - Ammonium chloride is an inorganic compound with formula NH4Cl. However, practically all hydrated metal ions other than those of the alkali metals ionize to give acidic solutions. then you must include on every digital page view the following attribution: Use the information below to generate a citation. Legal. When we mix solutions of an acid and a base, an acid-base neutralization reaction occurs. Effects of Ammonia on the Absorption and Accumulation of Glucose, If we want to determine a Kb value using one of these handbooks, we must look up the value of Ka for the conjugate acid and convert it to a Kb value. salt hydrolysis: A reaction in which one of the ions from a salt reacts with water, forming either an acidic or basic solution. Now we have the ionization constant and the initial concentration of the weak acid, the information necessary to determine the equilibrium concentration of H3O+, and the pH: With these steps we find [H3O+] = 2.3 103 M and pH = 2.64, \(K_a\ce{(for\:NH4+)}=5.610^{10}\), [H3O+] = 7.5 106 M. \(\ce{C6H5NH3+}\) is the stronger acid (a) (b) . NH4Cl is not a base as it does not fit into the definition of base given by any of the acid-base theory viz. 2 2 In anionic hydrolysis, the pH of the solution will be above 7. Screen capture done with Camtasia Studio 4.0. This conjugate base is usually a weak base. There are a number of examples of acid-base chemistry in the culinary world. Jan 29, 2023. Ammonium Chloride is denoted by the chemical formula NH4Cl. It is soluble in liquid ammonia, hydrazine, and slightly soluble in acetone. What is net ionic equation for the reaction of AGNO3 NH4CL? Ammonium chloride in its aqueous solution is acidic as it releases hydronium upon its dissociation in a solution. \(\ce{Al(H2O)6^3+}(aq)+\ce{H2O}(l)\ce{H3O+}(aq)+\ce{Al(H2O)5(OH)^2+}(aq) \hspace{20px} K_\ce{a}=1.410^{5}\). It is isolated as aniline hydrochloride, \(\ce{[C6H5NH3+]Cl}\), a salt prepared by the reaction of the weak base aniline and hydrochloric acid. Therefore, ammonium chloride is an acidic salt. The reaction is: We are given two of three equilibrium concentrations and asked to find the missing concentration. Ionization increases as the charge of the metal ion increases or as the size of the metal ion decreases. There are a number of examples of acid-base chemistry in the culinary world. This may seem obvious from the ion's formula, which indicates no hydrogen or oxygen atoms, but some dissolved metal ions function as weak acids, as addressed later in this section. The following four situations illustrate how solutions with various pH values can arise following a neutralization reaction using stoichiometrically equivalent quantities: Our stomachs contain a solution of roughly 0.03 M HCl, which helps us digest the food we eat. Aniline is an amine that is used to manufacture dyes. The lining of the esophagus is not protected from the corrosive effects of stomach acid the way the lining of the stomach is, and the results can be very painful. The vegetable, such as a cucumber, is placed in a sealed jar submerged in a brine solution. So, Is NH4Cl an acid or base? Substituting the expressions for the equilibrium concentrations into the equation for the ionization constant yields: \(=\dfrac{(x)(x)}{0.10x}=1.4 \times 10^{5}\), \[\ce{[H3O+]}=0+x=1.210^{3}\:M \nonumber \], \[\mathrm{pH=log[H_3O^+]=2.92(an\: acidic\: solution)} \nonumber \]. The chloride ion has no effect on the acidity of the solution since HCl is a strong acid. We frequently see the formula of this ion simply as Al3+(aq), without explicitly noting the six water molecules that are the closest ones to the aluminum ion and just describing the ion as being solvated in water (hydrated). One of the most common antacids is calcium carbonate, CaCO3. The equation goes as this: NH4Cl +H2O === NH3 + H+ + Cl . The arithmetic checks; when 1.2 103 M is substituted for x, the result = Ka.