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Weak-acid

Most acidic substances are weak acids and therefore only partially ionized in aqueous solution ( FIGURE 16.9). We can use the equilibrium constant for the ionization reaction to express the extent to which a weak acid ionizes. If we represent a general weak acid as HA, we can write the equation for its ionization in either of the following ways, depending on whether the hydrated proton is represented as H.30 aq) or H aq)  [Pg.666]

Because H2O is the solvent, it is omitted from the equilibrium-constant expression. (Section 15.4) Thus, we can write the equilibrium-constant expression as either [Pg.666]

As we did for the ion-product constant for the autoionization of water, we change the subscript on this equihbrium constant to indicate the type of equation to which it corresponds  [Pg.666]

The subscript a denotes that is an equilibrium constant for the ionization of an acid, so Kg is called the acid-dissociation constant. [Pg.667]

The magnitude of indicates the tendency of the acid to ionize in water The larger the value of K , the stronger the acid. Chlorous acid (HCIO2), for example, is the strongest acid in Table 16.2, and phenol (HOCgH5) is the weakest. For most weak acids values range from 10 to 10 [Pg.668]

It is a common mistake to oonfuse the terms strong and weak acids with the terms concentrated and dilute acids. Can you state the difference between these terms  [Pg.500]

In contrast to HCl, HP is a weak acid, one that does not completely ionize in solution. [Pg.500]

When HP dissolves in water, only a fraction of the dissolved molecules ionize into HsO and ions. The solution contains many intact HP molecules. [Pg.500]

I Notice that the strength of a conjugate base is related to its attraction to in solution. [Pg.500]

Solutions such as these are called weak electrolyte solutions. [Pg.501]

These equilibria are in aqueous solution, so we will use equilibrium-constant expressions based on concentrations. Because H2O is the solvent, it is omitted from the equilibrium-constant expression, ogo (Section 15.4) Further, we add a subscript a on the equilibrium constant to indicate that it is an equilibrium constant for the ionization of an acid. Thus, we can write the equilibriimi-constant expression as either  [Pg.686]

Based on the entries in Table 16.2, which element is most commonly bonded to the acidic hydrogen  [Pg.687]

In order to calculate either the value for a weak acid or the pH of its solutions, we will use many of the skills for solving equdibriiun problems developed in Section 15.5. In memy cases the small magnitude of cJlows us to use approximations to simplify the problem. In doing these calculations, it is important to realize that proton-transfer reactions are generally very rapid. As a result, the measured or calculated pH for a weak acid cdways represents an equilibrium condition. [Pg.688]

A student prepared a 0.10 M solution of formic acid (HCOOH) and found its pH at 25 °C to be 2.38. Calculate for formic acid at this temperature. [Pg.688]

Suppose that you dissolve acetic acid (CH3COOIQ in water. It reacts with the water molecules, donating a proton and forming hydronium ions. It also establishes equilibrium, where you have a significant amount of unionized acetic acid. (In reactions that go to completion, the reactants are completely used up creating the products. But in equilibrium systems, two exactly opposite chemical reactions — one on each side of the reaction arrow — are occurring at the same place, at the same time, with the same speed of reaction. For a discussion of equilibrium systems, see Chapter 8.) [Pg.199]

If you want to see whether a person is a chemist, ask him to pronounce unionized A chemist pronounces it un-ionized, meaning not ionized. Everyone else pronounces it union-ized, meaning being part of a union.  [Pg.199]

The acetic acid reaction with water looks like this  [Pg.199]

The acetic acid that you add to the water is only partially ionized. In the case of acetic acid, about 5 percent ionizes, while 95 percent remains in the molecular form. The amount of hydronium ion that you get in solutions of acids that don t ionize completely is much less than it is with a strong acid. Acids that only pmUally ionize are called weak acids. [Pg.199]

Calculating the hydronium ion concentration in weak acid solutions isn t as straightforward as it is in strong solutions, because not all of the weak acid that dissolves initially has ionized. In order to calculate the hydronium ion concentration, you must use the equilibrium constant expression for the weak acid. Chapter 8 covers the K, expression that represents the equilibrium system. For weak acid solutions, you use a modified equilibrium constant expression called the K, — the acid ionization constant Take a look at the generalized ionization of some weak acid HA  [Pg.199]

When HP dissolves in water, only a fraction of the molecules ionize. [Pg.704]

Notice that two of the weak acids in Table 15.4 are diprotic, meaning that they have two ionizable protons, and one is triprotic (three ionizable protons). We discuss polyprotic acids in more detail in Section 15.9. [Pg.704]

We can also write the formulas for acetic acid and formic acid as CH3COOH and HCOOH, respectively, to indicate that in these compounds the only H that ionizes is the one attached to an oxygen atom. [Pg.704]


The strength of an acid is measured by the value of its dissociation constant, strong acids, e.g. HCl, HNO3. being substantially fully ionized in solution and weak acids predominately unionized. [Pg.12]

K2 is called the hydrolysis constant for sodium ethanoate. Hydrolysis occurs when salts involving weak acids or bases are dissolved in water. It is often also found with metal ions in solution. The ion [M(H20) ] dissociates to the hydroxy species [M(H20) , (OH)]f 1. ... [Pg.211]

Nitroxylic acid, HiNO . Yellow NajNOa formed by electrolysis NaN02 in NHj. Structure unknown free acid unknown. Nitramide, H2NNO2. A weak acid. [Pg.279]

Examples of the lader include the adsorption or desorption of species participating in the reaction or the participation of chemical reactions before or after the electron transfer step itself One such process occurs in the evolution of hydrogen from a solution of a weak acid, HA in this case, the electron transfer from the electrode to die proton in solution must be preceded by the acid dissociation reaction taking place in solution. [Pg.603]

Values of are small for weak acids and they range very widely (Table 4.1). It is common practice to quote values as the negative logarithm to the base ten, i.e. — logjo K.. since such numbers are less cumbersome and positive when Aj < 1. The symbol for -logio is by convention "p/ fhus -logjo becomes pK,. Table 4.1 shows some typical pAg values. [Pg.86]

Consider first two substances which have very similar molecules. He, hydrogen fluoride and HCl. hydrogen chloride the first is a Weak acid in water, the second is a strong acid. To see the reason consider the enthalpy changes involved when each substance in water dissociates to form an acid ... [Pg.87]

Thus, ihe strongly basic oxide ion attacks the weakly acidic SiOj in a molten salt as solvent (p. 187 ... [Pg.89]

But a solution of carbon dioxide in water behaves as a very weak acid since the effective dissociation constant K is given by ... [Pg.183]

Since carbonic acid is a weak acid, its salts are hydrolysed in aqueous solution ... [Pg.183]

Pure hydrazoic acid is a colourless liquid, b.p. 310 K. It is very ready to detonate violently when subjected to even slight shock, and so is used in aqueous solution. It is a weak acid, reacting with alkali to give azides, which contain the ion Nj. [Pg.224]

Arsenic(IH) acid is an extremely weak acid in fact, the oxide is amphoteric, since the following equilibria occur ... [Pg.236]

Nitrous acid, HNOj, is known as a gas, but otherwise exists only in solution, in which it is a weak acid. Hence addition of a strong acid to a solution of a nitrite produces the free nitrous acid in solution. [Pg.243]

The addition of even a weak acid (such as ethanoic acid) to a nitrite produces nitrous acid which readily decomposes as already indicated. Hence a nitrite is distinguished from a nitrate by the evolution of nitrous fumes when ethanoic acid is added. [Pg.244]

It is an extremely weak acid but does form salts. Two kinds are known, trioxoarsenates(III), for example Na3As03, and dioxo-arsenates(III), for example Cu(As02)2-... [Pg.247]

Hydrogen sulphide is slightly soluble in water, giving an approximately 0.1 M solution under 1 atmosphere pressure it can be removed from the solution by boiling. The solution is weakly acidic and dissolves in alkalis to give sulphides and hydrogensulphides. The equilibrium constants... [Pg.283]

Since the hydrogen-element bond energy decreases from sulphur to tellurium they are stronger acids than hydrogen sulphide in aqueous solution but are still classified as weak acids—similar change in acid strength is observed for Group Vll hydrides. [Pg.284]

These are ionic solids and can exist as the anhydrous salts (prepared by heating together sulphur with excess of the alkali metal) or as hydrates, for example Na2S.9HjO. Since hydrogen sulphide is a weak acid these salts are hydrolysed in water,... [Pg.287]

Tellurium trioxide, TeOa, is an orange yellow powder made by thermal decomposition of telluric(VI) acid Te(OH)g. It is a strong oxidising agent which will, like H2Se04, oxidise hydrogen chloride to chlorine. It dissolves in hot water to give telluric(VI) acid. This is a weak acid and quite different from sulphuric and selenic acids. Two series of salts are known. [Pg.305]

The bond dissociation energy of the hydrogen-fluorine bond in HF is so great that the above equilibrium lies to the left and hydrogen fluoride is a weak acid in dilute aqueous solution. In more concentrated solution, however, a second equilibrium reaction becomes important with the fluoride ion forming the complex ion HFJ. The relevant equilibria are ... [Pg.328]

Aqueous hydrogen fluoride is a weak acid (see above) and dissolves silica and silicates to form hexafluorosilicic acid hence glass is etched by the acid, which must be kept in polythene bottles. [Pg.330]

The acids of chlorine(I), bromine(I) and iodine(I) are weak acids, the pKa values being 7.4, 8.7 and 12.3 respectively. They are good oxidising agents, especially in acid solutions. The acids decrease in stability from chloric(I) to iodic(I). [Pg.337]

Only chlorine forms a -t-3 acid, HCIO2. This is also a weak acid and is unstable. The - -5 acids, HXO3, are formed by chlorine, bromine and iodine they are strong acids. They are stable compounds and all are weaker oxidising agents than the corresponding +1 acids. [Pg.337]

Chloric(III) acid is a fairly weak acid, and is an oxidising agent, for example it oxidises aqueous iodide ion to iodine. Sodium chlorate(III) (prepared as above) is used commercially as a mild bleaching agent it bleaches many natural and synthetic fibres without degrading them, and will also bleach, for example, oils, varnishes and beeswax. [Pg.339]

These are acids which can be regarded, in respect of their formulae (but not their properties) as hydrates of the hypothetical diiodine heptoxide, liO-j. The acid commonly called periodic acid , I2O7. 5H2O, is written HglO (since the acid is pentabasic) and should strictly be called hexaoxoiodic(VII) acid. It is a weak acid and its salts are hydrolysed in solution. It can be prepared by electrolytic oxidation of iodic(V) acid at low temperatures ... [Pg.342]

In dilute aqueous solution hydrogen fluoride is a weak acid but the acid strength increases with the concentration of hydrogen fluoride. [Pg.352]

Since hydroxylamine is usually available only in the form of its salts, e.g., the hydrochloride or sulphate, the aqueous solution of these salts is treated with sodium acetate or hydroxide to liberate the base before treatment with the aldehyde or ketone. Most oximes are weakly amphoteric in character, and may dissolve in aqueous sodium hydroxide as the sodium salt, from which they can be liberated by the addition of a weak acid, e.g., acetic acid. [Pg.93]

The addition of the sulphuric acid first neutralises the sodium hydroxide, and then gives a weakly acidic and therefore colourless solution. The sodium derivative (A) then undergoes further partial hydrolysis in order to re-establish the original equilibrium, and the sodium hydroxide thus formed again produces the pink coloration, which increases in depth as the hydrolysis proceeds. [Pg.134]


See other pages where Weak-acid is mentioned: [Pg.12]    [Pg.52]    [Pg.64]    [Pg.69]    [Pg.80]    [Pg.82]    [Pg.82]    [Pg.92]    [Pg.119]    [Pg.119]    [Pg.210]    [Pg.211]    [Pg.281]    [Pg.320]    [Pg.342]    [Pg.373]    [Pg.1103]    [Pg.86]    [Pg.87]    [Pg.87]    [Pg.88]    [Pg.114]    [Pg.115]    [Pg.55]   
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Absorption of weak acids

Acetic acid as weak electrolyte

Acid aqueous solution weak acids ionize only

Acid dissociation constant of weak acids

Acid dissociation constant weak adds

Acid dissociation constant weak bases

Acid strength weak acids

Acid-base equilibria problems weak acids

Acid-base equilibria problems weak bases

Acid-base equilibria weak acids

Acid-base equilibria weak bases

Acid-base equilibrium problems with weak acids

Acid-base strengths acids weak bases

Acidic components, weak

Acidity weakly basic probes

Acids for weak

Acids strong and weak

Acids weak varieties

Acids, acid weak, deprotonation

Acids, deprotonation of weak, with

Adsorption weak acid

As weak acid

Bronsted acids, weak

Buffer weak acid plus its salt with a strong base

Buffered solutions titrations with weak acids

Calcium carbonate reaction with weak acid

Calculating the pH of Weak Acid Solutions

Calculation of pH in weak acid solutions

Calculations on equilibria weak acids

Carbonic acid, weak

Cation weak acid

Chemical equilibrium weak acid

Concentration of weak acids

Concentration weak-acid equilibrium problem

Conductance studies weak acids/bases

Conjugate acid, of a weak base

Constants for Weak Monoprotic Acids and Bases

Cyanides, weak-acid dissociable

Dilute weak acids

Dissociation (Ionization) Constants of Weak Acids

Dissociation constant of weak acids

Dissociation of weak acid

Dissociation, weak acids/bases

Electrosynthesis of complexes containing weakly acidic anions

Equilibria Involving Weak Acids and Bases

Equilibrium constant weak acid

Equilibrium expression weak acid

Equilibrium weak acid

Equivalence point weak acid-strong base

Hydrochloric acid weak base solution/water

Hydroxide ions reaction with weak acid

Hydroxide ions weak acid-strong base

Ion weak acid

Ionisation of weak acids

Ionisation weakly acidic/basic drugs

Ionization constants of weak acids

Ionization of weak acid

Ionization of weak acids and bases

Lewis acid sites weak acidity

Lewis acidity weak sites

Methods Used to Measure Weak Acid Strength

Mixtures of weak acids

Moderately weak acids

Monoprotic Weak Acid, HA (or Base, B)

Naturally occurring weak organic acids

Of weak acids

Phenol, weak acid

Potassium hydroxide, deprotonation weak acids with

Potentiometric titrations of weak acids

Proton acids, weak

Proton acids, weak hydrobromide

Protonation weak acid

Pyridones weak acids

Radical weak acids

Reactions of very weakly basic acids and esters

Salts of Strong Bases and Weak Acids

Salts of weak acids

Sodium hydroxide weak acid-strong base titration

Solubility of Weak Acids and Dissociation Constant

Solubility of weak acids

Solubility weak acid salts

Solubilization weak acids

Solutes weak acids

Solutions of a Weak Acid or Base

Solving Problems Involving Weak-Acid Equilibria

Spreadsheet weak acid titration curve

Strengths of Weak Bronsted Acids

Strong Acids and Their Corresponding Weak Bases

Strong acid-weak base

Strong bases titrations with weak acid

Suppressing effect of weak acids

Surfactants weakly acidic

The Monoprotic Weak Acid-Strong Base Curve

The Titration of Weak Acids and Bases

The weak acid where both approximations are valid

The weak acid where both approximations can be made

Titration calculations weak acid

Titration curve weak acid, strong base

Titration of Weak Acid with Strong Base

Titration of Weak Monoprotic Acids

Titration of weak acids and bases

Titration strong acid/weak base

Titrations of weak acids

Tools for Dealing with Weak Acids and Bases

Utterly Confused About Weak Acids and Bases

Very weak acids

Water reaction with weak acids

Waxes Weak acids

Weak Acid Processes

Weak Acids Make Strong Bases (and Vice Versa)

Weak Acids and Acid Ionization Constants

Weak Acids and Their Equilibrium Constants

Weak Acids reduction

Weak Base versus Strong Acid

Weak Lewis acid

Weak Monoprotic Acids

Weak acid amphiprotic

Weak acid anions

Weak acid catalysis

Weak acid cation resin

Weak acid cation-exchange

Weak acid cation-exchange columns

Weak acid conjugate

Weak acid diprotic

Weak acid dissociation constants

Weak acid effluent

Weak acid equivalence point

Weak acid fractional composition

Weak acid intermediate form

Weak acid pH calculation

Weak acid percent dissociation

Weak acid percent ionization

Weak acid polyprotic titration

Weak acid principal species

Weak acid reaction with base

Weak acid response element

Weak acid salts

Weak acid solubility

Weak acid-strong base types

Weak acid/base

Weak acidic leaching

Weak acids Henderson-Hasselbalch equation

Weak acids acetic acid

Weak acids adaptation

Weak acids and bases

Weak acids as indicators

Weak acids buffered solutions

Weak acids buffering capacity

Weak acids calculating

Weak acids carbamic acid

Weak acids carboxylic

Weak acids common

Weak acids conjugate base

Weak acids curves)

Weak acids defined

Weak acids definition

Weak acids describing behavior

Weak acids determination

Weak acids dissolving in water

Weak acids equilibrium problems

Weak acids equilibrium problems with

Weak acids functional groups

Weak acids gastrointestinal absorption

Weak acids group 15 oxoacids

Weak acids group 16 hydrides

Weak acids hydrocyanic acid

Weak acids hydrogen fluoride

Weak acids hypochlorous acid

Weak acids indicators

Weak acids ionization

Weak acids mixture

Weak acids naturally occurring

Weak acids nitrous acid

Weak acids organic

Weak acids physiologic significance

Weak acids physiological actions

Weak acids polyprotic

Weak acids potentiometric titration

Weak acids properties

Weak acids reaction with hydroxide

Weak acids resistance

Weak acids simplifying assumptions

Weak acids soluble salts

Weak acids solution

Weak acids strength

Weak acids strong

Weak acids strong base reactions with

Weak acids titration

Weak acids, continued

Weak acids, drugs

Weak acids, ionization constants

Weak acids, uptake from soil

Weak hydrogen bonds soft acids

Weak organic bases or acids that degrade the pH gradients across membranes

Weak proton acids, reaction

Weak sulfuric acid

Weak sulfuric acid attack, example

Weak sulfuric acid corrosion

Weak-Acid Ion Exchangers

Weak-acid anion exchangers

Weak-acid cation exchangers

Weak-acid equilibrium problem solving

Weak-acid equilibrium problem solving concentrations

Weak-acid hypothesis

Weak-acid hypothesis evidence

Weak-acid resins

Weak-acid resins ion exchange

Weakly Acidic and Neutral Medium

Weakly acidic

Weakly acidic

Weakly acidic and basic drugs

Weakly acidic cation

Weakly acidic groups

Weakly acidic medium

Weakness of acidity

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