Acid/base neutralization equations

The last definition has widespread use in the volumetric analysis of solutions. If a fixed amount of reagent is present in a solution, it can be diluted to any desired normality by application of the general dilution formula V,N, = V N. Here, subscripts 1 and 2 refer to the initial solution and the final (diluted) solution, respectively V denotes the solution volume (in milliliters) and N the solution normality. The product VjN, expresses the amount of the reagent in gram-milliequivalents present in a volume V, ml of a solution of normality N,. Numerically, it represents the volume of a one normal (IN) solution chemically equivalent to the original solution of volume V, and of normality N,. The same equation V N, = V N is also applicable in a different context, in problems involving acid-base neutralization, oxidation-reduction, precipitation, or other types of titration reactions. The justification for this formula relies on the fact that substances always react in titrations, in chemically equivalent amounts. 

K.20 Classify each of the following reactions as precipitation, acid-base neutralization, or redox. If a precipitation reaction, write a net ionic equation if a neutralization reaction, identify the acid and the base if a redox reaction, identify the oxidizing agent and the reducing agent. 

Which of the following does NOT represent a balanced equation for an acid-base neutralization reaction ... 

In an acid-base neutralization reaction, the hydronium (hydrogen) ions of the acidic solution react with the hydroxide ions in the basic solution. The reaction may be shown by this equation. 

As in Section 4.3, acid-base neutralization reactions will be illustrated here. In order to calculate the equivalent weight of an acid, the balanced equation representing the reaction in which the solution is to be used is needed so that the number of hydrogens lost per formula in the reaction can be determined. The equivalent weight of an acid is the formula weight of the acid divided by the number of hydrogens lost per molecule (see Section 4.3). 

J.6 Determine the salt that is produced from the acid-base neutralization reaction between (a) potassium hydroxide and acetic acid, CH3COOH (b) ammonia and hydroiodic acid (c) barium hydroxide and sulfuric acid (both H atoms react) (d) sodium hydroxide and hydrocyanic acid, HCN. Write the full ionic equation for each reaction. 

To see how titration works, let s imagine that we have an HC1 solution (an acid) whose concentration we want to find by allowing it to react with a base such as NaOH in what is called a neutralization reaction. (We ll learn more about acid-base neutralization reactions in the next chapter.) The balanced equation is... 

There are three important classes of aqueous reactions. Precipitation reactions occur when solutions of two ionic substances are mixed and a precipitate falls from solution. To predict whether a precipitate will form, you must know the solubility of each potential product. Acid-base neutralization reactions occur when an acid is mixed with a base, yielding water and a salt. The neutralization of a strong acid with a strong base can be written as a net ionic equation, in which nonparticipating, spectator ions are not specified ... 

Write the balanced chemical equation for the acid-base neutralization of the excess unreacted HCl with the NaOH. 

Write balanced formula equations for the following acid-base neutralization reactions. 

Arrhenius and Bronsted-Lowry acid-base neutralization reactions all have one thing in common. They involve the reaction of an acid with a base to form a salt that contains the cation characteristic of the base and the anion characteristic of the acid. Water is also usually formed. This is indicated in the formula unit equation. The general form of the net ionic equation, however, is different for different acid-base reactions. The net ionic equations depend on the solubility and extent of ionization or dissociation of each reactant and product. 

When deriving net-ionic equations, be certain to start with a balanced formula equation. That way, you will end up with a balanced net-ionic equation. The formula, ionic and net-ionic equations for the reaction between hydrochloric and calcium hydroxide appear below. The net-ionic equation shows that acid-base neutralization here is the same reaction seen in the nitric add-sodium hydroxide reaction. 

Redox titrations require the same type of calculations (based on the mole method) as acid-base neutralizations. The difference is that the equations and the stoichiometry tend to be more complex for redox reactions. The following is an example of a redox titration. 

This equilibrium is described by the constant of 3.1 X 1015 for the case of phosphates, and 4.7 X 1013 for acidic arsenates. For metavanadate solutions an estimation of the value of the similar constant failed owing to the levelling of the acidic properties of this Lux acid. The next stage of the titration is the formation of neutral salts as a result of acid-base neutralization of the formed pyro-anions, this stage is described by the following equation ... 

The curves from the direct and reverse potentiometric titration of metavanadate ions with the Lux bases NaOH and Na2C03 are presented in Fig. 1.2.14a. The neutralization process runs in two stages according to the equations (1.2.87) and (1.2.88), to which two small diffuse pO-drops (bends) in the potentiometric curves correspond. Nevertheless, these bends become apparent on the differential potentiometric titration curve, shown in Fig. 1.2.14b. The reverse titration results in two steps of neutralization, also, that confirms the reversibility of the process of the acid-base neutralization of vanadium(V) oxocompounds in molten Nal. Comparison with the corresponding dependencies for the molten equimolar KCl-NaCl... 

Acid-base (neutralization) reactions occur when an acid (an H" -yielding substance) and a base (an OH -yielding substance) react and the and OH ions form a water molecule. Strong acids and bases dissociate completely in water weak acids and bases dissociate slightly. In a titration, a known concentration of one reactant is used to determine the concentration of the other. An acid-base reaction can also be viewed as the transfer of a proton from an acid to a base. Because weak acids dissociate very little, equations involving them show the acid as an intact molecule. 

One requirement for a reaction to occur is that the chemicals involved must be able to mix and interact with one another. Thus the physical state of the reactants can be important. In particular, an aqueous solution is often used as the medium for a reaction. To describe reactions in the aqueous phase effectively, we often need to specify the molar concentration of the solutions used. We also have options about how to write the chemical reaction itself—as a molecular equation, for example, or a net ionic equation. Several classes of chemical reactions, such as precipitation reactions or acid-base neutralizations, are sufficiently common that additional definitions have been established to improve our ability to communicate about them. 

This leaves us with a dilemma, however. Sometimes it is important that the other ions, CT and Na+ in this example, be those speeified even though, or in fact precisely because, they do not participate in this reactiom Suppose we chose to illustrate acid-base neutralization by mixing dilute solutions of Ba(OH>2 and H2SO4. Now the equations above would be inadequate because of the simultaneous precipitation of BaS04. Here we will often resolve such problems by writing the conventional formulas when specific substances are required or mentioned in the text, but usually with the formulas of the predominant active species shown in equations. This last reaction, then, could be written, for the more-dilute acid, as ... 

STRATEGIZE Since this problem involves an acid-base neutralization reaction between HCl and NaOH, you start by writing the balanced equation, using the techniques covered earlier in this section. 

Acid-Base Neutralization Reactions. As defined in Chapter 4, adds and bases can either be weak or strong. In the case of the reaction between a strong acid and a strong base, an exchange reaction occurs. For example, hydrochloric acid and potassium hydroxide react in an exchange manner to form hydrogen hydroxide (WATER ) and potassium chloride. Potassium chloride is not an exception and is therefore soluble. The molecular equation can be written as... 

Acetic acid, CH3COOH, is a weak acid and NaOH is a strong base. The reaction between CH3COOH and NaOH is an acid-base neutralization reaction. We start by writing a balanced chemical equation for the reaction. We must convert mL NaOH to g CH3COOH. The necessary conversions are as follows ... 

Hydrazinium salts, N2H5 X, are acids in anhydrous hydrazine, metallic hydrazides, N2H, are bases. Neutralization in this solvent system involves the hydrazinium and hydrazide ions and is the reverse of equation 7. Metal hydrazides, formally analogous to the metal amides, are prepared from anhydrous hydrazine and the metals as well as from metal amides, alkyls, or hydrides. (The term hydrazide is also used for organic compounds where the carboxyUc acid OH is substituted with a N2H2.) Sodium hydrazide [13598-47-5] is made from sodium or, more safely, from sodium amide (14) ... 

There is considerable evidence to indicate that the neutralization reaction occurs when any strong base reacts with any strong acid in water solution. It follows that the neutralization equation written above applies to any strong acid-strong base reaction. 

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