Precipitation: If the reaction forms a solid, then a precipitate will form during the titration. Precipitation: If a reaction produces a solid, a precipitate will form during the titration. The chemical reaction After adding 50.00 mL of 0.05619 M AgNO3 and allowing the precipitate to form, the remaining silver is back titrated with 0.05322 M KSCN, requiring 35.14 mL to reach the end point. Let’s use the titration of 50.0 mL of 0.0500 M NaCl with 0.100 M AgNO3. Precipitation Reaction. know that the amount of silver ion used to the equivalence point equals the amount of A second type of indicator uses a species that forms a colored complex with the titrant or the titrand. Another method for locating the end point is a potentiometric titration in which we monitor the change in the titrant’s or the titrand’s concentration using an ion-selective electrode. The stoichiometry of the reaction requires that, \[\text{mol Ag}^+ = M_\text{Ag}V_\text{Ag} = M_\text{Cl}V_\text{Cl} = \text{mol Cl}^- \nonumber\], \[V_{eq} = V_\text{Ag} = \frac{M_\text{Cl}V_\text{Cl}}{M_\text{Ag}} = \frac{(0.0500 \text{ M})(50.0 \text{ mL})}{0.100 \text{ M}} = 25.0 \text{ mL} \nonumber\]. Cloudy … A titration is an analytical procedure in which a reagent called a titrant Each mole of I– consumes one mole of AgNO3 and each mole of KSCN consumes one mole of AgNO3; thus, \[\text{mol AgNO}_3 = \text{mol I}^- + \text{mol KSCN} \nonumber\], \[\text{mol I}^- = \text{mol AgNO}_3 - \text{mol KSCN} = M_\text{Ag} V_\text{Ag} - M_\text{KSCN} V_\text{KSCN} \nonumber\], \[\text{mol I}^- = (0.05619 \text{ M})(0.0500 \text{ L}) - (0.05322 \text{ M})(0.03514 \text{ L}) = 9.393 \times 10^{-4} \nonumber\], \[\frac{(9.393 \times 10^{-4} \text{ mol I}^-) \times \frac{126.9 \text{ g I}^-}{\text{mol I}^-}}{0.6712 \text{ g sample}} \times 100 = 17.76 \text{% w/w I}^- \nonumber\]. A typical calculation is shown in the following example. 100.0 mL solution containing 0.100 M NaCl was titrated with 0.100 M AgNO3 and … In a precipitation titration, the stoichiometric reaction is a reaction which produces Stoichiometric, rapid. This kind of titration is based on precipitation reactions, i.e. Precipitation Titration Definition. Precipitation Titration Definition. Titration … After the equivalence point, Ag+ is in excess and the concentration of Cl– is determined by the solubility of AgCl. or a pCl of 7.81. a titrant is added to precipitate the analyte. One of the earliest precipitation titrations—developed at the end of the eighteenth century—was the analysis of K 2 CO 3 and K 2 SO 4 in potash. if it is in the form of a solution. For a discussion of potentiometry and ion-selective electrodes, see Chapter 11. Copy. By: Rahul Malik By: Rahul Malik March, 2016 March, 2016. The solubility of a dissociated sparingly soluble compound is determined by the maximum ionic product or solubility product K S.. Although precipitation titration is rarely listed as a standard method of analysis, it may still be useful as a secondary analytical method for verifying other Titration of a strong acid with a strong base. Calcium nitrate, Ca(NO3)2, was used as the titrant, which forms a precipitate of CaCO3 and CaSO4. product of silver chromate will then be exceeded and a red precipitate of. Method Mohr Volhard Fajans. A back titration is useful if the endpoint of the reverse titration is easier to identify than the endpoint of the normal titration, as with precipitation reactions. Precipitation titrations are mainly based on the formation of the precipitate by the reaction of the sample with precipitating agents. CHEM 301 LECTURE. As a result, the end point is always later than the equivalence point. By: Rahul Malik By: Rahul Malik March, 2016 March, 2016. At The method is widely used for silver and chloride, because the titration can be done in an acidic solution. Precipitation titration Precipitation titration is a titration method based on the formation of precipitate, which is slightly soluble Titration with precipitating agents is useful for determining certain analytes, provided the equilibrium will take place rapidly and suitable means of detecting equivalent points is available Titration … Method Mohr Volhard Fajans. Record the initial volume of AgNO 3 … Unit 9. An example of a precipitation titration reaction is the Mohr method, which is used to find the concentration of halide ions in solution (particularly Cl- and Br-). It is a titrimetric method which involves the formation of precipitates during the experiment of titration. The first task is to calculate the volume of NaCl needed to reach the equivalence point; thus, \[V_{eq} = V_\text{NaCl} = \frac{M_\text{Ag}V_\text{Ag}}{M_\text{NaCl}} = \frac{(0.0500 \text{ M})(50.0 \text{ mL})}{0.100 \text{ M}} = 25.0 \text{ mL} \nonumber\], Before the equivalence point the titrand, Ag+, is in excess. In-structions for performing some of the most commonly used applications are given in this booklet together with The Mohr method was first published in 1855 by Karl Friedrich Mohr. Share. At the beginning of this section we noted that the first precipitation titration used the cessation of precipitation to signal the end point. We begin by calculating the titration’s equivalence point volume, which, as we determined earlier, is 25.0 mL. other sections this notation, in the form of pH, is extensively used to express the A reaction in which the analyte and titrant form an insoluble precipitate also can serve as the basis for a titration. Subtracting the end point for the reagent blank from the titrand’s end point gives the titration’s end point. it. Precipitation titration is an Amperometric titration … Example problem in which titration being performed is precipitation reaction. the concentration of silver ion or the the concentration of chloride ion which occurs at To calculate their concentrations we use the Ksp expression for AgCl; thus. Reaction involve is as follows – AgNO 3 + NaCl AgCl + NaNO 3. The analysis for I– using the Volhard method requires a back titration. concentration and volume, of the other reactant required to reach the endpoint of the Share On. It is type of titremetric procedure involves the formation of precipitate during the course of Titration. is slowly added to another substance. A white precipitate of AgCl is deposited on the bottom of the flask during the course Example (1): If the solubility of AgCl is 0.0015 g/l what is the solubility product. The determination limit for precipitation titrations depends very strongly on the solubility product.. A simple equation takes advantage of the fact that the sample contains only KCl and NaBr; thus, \[\text{g NaBr} = 0.3172 \text{ g} - \text{ g KCl} \nonumber\], \[\frac{\text{g KCl}}{74.551 \text{g KCl/mol KCl}} + \frac{0.3172 \text{ g} - \text{ g KCl}}{102.89 \text{g NaBr/mol NaBr}} = 4.048 \times 10^{-3} \nonumber\], \[1.341 \times 10^{-2}(\text{g KCl}) + 3.083 \times 10^{-3} - 9.719 \times 10^{-3} (\text{g KCl}) = 4.048 \times 10^{-3} \nonumber\], \[3.69 \times 10^{-3}(\text{g KCl}) = 9.65 \times 10^{-4} \nonumber\], The sample contains 0.262 g of KCl and the %w/w KCl in the sample is, \[\frac{0.262 \text{ g KCl}}{0.3172 \text{ g sample}} \times 100 = 82.6 \text{% w/w KCl} \nonumber\]. One type of titration is precipitation titration which started in the early 18 th century and was considered as the oldest analytical techniques. The first task is to calculate the volume of Ag+ needed to reach the equivalence point. Calculate the titration curve for the titration of 50.0 mL of 0.0500 M AgNO3 with 0.100 M NaCl as pAg versusVNaCl, and as pCl versus VNaCl. The following table summarizes additional results for this titration. Precipitation Titration :-It is also known as Argintometric Titration. Title: Potentiometric Precipitation Titration Example 1 Potentiometric Precipitation Titration Example. Precipitation Titration Curve In precipitation titration curve, a graph is drawn between change in titrant’s concentration as a function of the titrant’s volume. 7. Precipitation titration. used not only in titrations but for the general expression of solution concentrations. Precipitation Titration: Determination of Chloride by the Mohr Method by Dr. Deniz Korkmaz Introduction Titration is a process by which the concentration of an unknown substance in solution is determined by adding measured amounts of a standard solution that reacts with the unknown. In the Fajans method for Cl– using Ag+ as a titrant, for example, the anionic dye dichlorofluoroscein is added to the titrand’s solution. The precision of measurement of burettes and pipettes are given in Because \(\text{CrO}_4^{2-}\) imparts a yellow color to the solution, which might obscure the end point, only a small amount of K2CrO4 is added. The logarithmic p notation is commonly To determine the concentration of chloride ion in a … Titrations Precipitation titration • If the K sp of a compound is small, we can use precipitation as a means to determine the analyte concentration For example: Ag+(aq) + I-(aq) AgI(s) K sp = 8.3 x 10-17 Add Ag+ to determine [I-] Titrations Precipitation titration … Since [CrO42-] = 10-3 molar, [Ag+]2 • The reactions employed in the precipitation titrations must fulfill the requirements of reactions used in titrimetric analysis. concentration or activity is used rather than the concentration or activity itself; that We know that, \[\text{mol KCl} = \frac{\text{g KCl}}{74.551 \text{g KCl/mol KCl}} \nonumber\], \[\text{mol NaBr} = \frac{\text{g NaBr}}{102.89 \text{g NaBr/mol NaBr}} \nonumber\], which we substitute back into the previous equation, \[\frac{\text{g KCl}}{74.551 \text{g KCl/mol KCl}} + \frac{\text{g NaBr}}{102.89 \text{g NaBr/mol NaBr}} = 4.048 \times 10^{-3} \nonumber\]. An initial fast titration will be performed with this sample to determine the approximate endpoint. Ex. In the Volhard method for Ag+ using KSCN as the titrant, for example, a small amount of Fe3+ is added to the titrand’s solution. to the amount of chloride ion originally present. a titrant is added to precipitate the analyte. When silver nitrate … is yellow while a solution or precipitate of Ag2CrO4 is blood-red. Let’s calculate the titration curve for the titration of 50.0 mL of 0.0500 M NaCl with 0.100 M AgNO3. Ag+ + … this endpoint has been reached. Calculate the %w/w Ag in the alloy. 13-10 The CO in a 20.3-L sample of gas was converted to CO2 by passing the gas over iodine pentoxide heated to 150℃, and I2 was distilled and collected to 8.25 mL of 0.01101 M Na2S2O3, then back titration with 2.16 mL of 0.00947 M I2 solution. The solubility point, addition of more silver ion will continue to reduce the concentration of chloride For those Volhard methods identified with an asterisk (*), the precipitated silver salt is removed before carrying out the back titration. titration. It requires 38.5 mL of the acid to titrate the ammonia. after the equivalence point has been reached, there is no more chloride ion to react with Copy. Figure \(\PageIndex{2}\)b shows pCl after adding 10.0 mL and 20.0 mL of AgNO3. In a precipitation titration of 46.00 mL of a chloride solution of unknown concentration, 31.00 mL of 0.6973 molar AgNO 3 were required to reach the equivalence point. It A sample of an ammonia solution is titrated with 0.100 M hydrochloric acid. The titrant reacts with the analyte and forms an insoluble substance. Silver nitrate is an important precipitating reagent which can also be used for the determination of the halogens, halogenlike anions, mercaptans, fatty acids, and several divalent inorganic anions. A precipitation reaction is a chemical reaction that occurs in aqueous solution and form precipitates. Worked Example: Precipitation Titration of KCl (aq) with AgNO 3(aq). Note, that in the real world it is quite often necessary to account for numerous side reactions - especially for protonation and hydrolysis of both metal cation and ligand. PRECIPITIMETRY. The purpose of a titration is to determine the amount, or The presence of the first slight excess of silver ion (i.e., the end… The determination limit for precipitation titrations depends very strongly on the solubility product.. Although precipitation titrimetry rarely is listed as a standard method of analysis, it is useful as a secondary analytical method to verify other analytical methods. Precipitation titrations also can be extended to the analysis of mixtures provided there is a significant difference in the solubilities of the precipitates. The titration’s end point is the formation of a reddish-brown precipitate of Ag2CrO4. After the equivalence point, the titrant is in excess. of chloride ion in a particular solution, one could titrate this solution with a solution Permalink. equivalence point of the titration is reached--the point at which the stoichiometric In the Mohr method for Cl– using Ag+ as a titrant, for example, a small amount of K2CrO4 is added to the titrand’s solution. Beyond the equivalence calculated for either ion if the other is known. Upon the addition of silver nitrate solution, precipitate was formed which indicates the presence of chloride ions in the sample. In forming the precipitates, each mole of KCl consumes one mole of AgNO3 and each mole of NaBr consumes one mole of AgNO3; thus, \[\text{mol KCl + mol NaBr} = 4.048 \times 10^{-3} \text{ mol AgNO}_3 \nonumber\], We are interested in finding the mass of KCl, so let’s rewrite this equation in terms of mass. Table \(\PageIndex{2}\) provides a list of several typical precipitation titrations. We also acknowledge previous National Science Foundation support under grant numbers 1246120, 1525057, and 1413739. follows: 31.00 mL x 0.6973 molar = 21.62 mmol Ag+ = 21.62 mmol Cl-, 21.62 mmol Cl-/46.00 mL Cl- = 0.4700 molar Cl-. There are three general types of indicators for a precipitation titration, each of which changes color at or near the titration’s equivalence point. the equivalence point, [Ag+] = [Cl-] and [Ag+]2 There are two precipitates in this analysis: AgNO3 and I– form a precipitate of AgI, and AgNO3 and KSCN form a precipitate of AgSCN. Precipitation titration » Curve calculation According to the general guidelines we will calculate concentration before the equivalence point assuming titrant was a limiting reagent - thus concentration of titrated substance is that of unreacted excess. A titration in which Ag+ is the titrant is called an argentometric titration. Precipitation Titrations INTRODUCTION. This usually makes it difficult to determine the endpoint precisely. Visit to learn more. 2 Here titrant reacts with titrand to form an insoluble precipitate. 2. 1/1. In this section we demonstrate a simple method for sketching a precipitation titration curve. For special … The concentration of unreacted Ag+ after adding 10.0 mL of NaCl, for example, is, \[[\text{Ag}^+] = \frac{(0.0500 \text{ M})(50.0 \text{ mL}) - (0.100 \text{ M})(10.0 \text{ mL})}{50.0 \text{ mL} + 10.0 \text{ mL}} = 2.50 \times 10^{-2} \text{ M} \nonumber\], which corresponds to a pAg of 1.60. The concentration of silver ion may go up to say 10-3 molar. Volumetric precipitation titrations Page 3 precipitation titrations • Precipitation titrations are volumetric methods based on the formation of a slightly soluble precipitate. of Ag+ and Cl-5) Precipitation titration curve is influenced by KSP value (completeness of reaction) . The most important precipitating reagent is silver nitrate. That's what we will do in the following example. an earlier section. Precipitation titrations. Add 2 drops of dichlorofluorescein indicator solution and just enough dextrin to cover the end of the tip of a spatula to one of the three beakers. The substance to be titrated is generally measured into the titration vessel either Unless otherwise noted, LibreTexts content is licensed by CC BY-NC-SA 3.0. 1 of1. directly, its mass (or density and volume) having been determined, or by pipet CHEM 301 LECTURE. In a precipitation titration of 46.00 mL of a chloride solution of unknown The quantitative relationship between the titrand and the titrant is determined by the stoichiometry of the titration reaction. The titrant solution is generally delivered from a buret. When calculating a precipitation titration curve, you can choose to follow the change in the titrant’s concentration or the change in the titrand’s concentration. A Presentation On. A precipitation titration curve is given below for 0.05M NaCl with 0.1M AgNO 3. A Presentation On. To determine the chloride ion concentration in a solution, we performed precipitation titration by Mohr method in this experiment. KCl (aq) → K + (aq) + Cl-(aq). Thus, it gives rise to a new element under some particular conditions. The most important applications are halide (especially chloride) and silver determinations. reactants is exhausted. The titrant react with the analyte forming an insoluble material and the titration continues till the very last amount of analyte is consumed. 5. Precipitation titration is used for such reaction when the titration is not recognized by changing the colors. As the supply of chloride ion is reduced to very low values, the Report the %w/w KCl in the sample. Titration of a strong acid with a strong base (continued) Titration of a weak acid with a strong base. The end point is found by visually examining the titration curve. The solubility of a dissociated sparingly soluble compound is determined by … Titration is an analytical chemistry technique used to find an unknown concentration of an analyte (the titrand) by reacting it with a known volume and concentration of a standard solution (called the titrant).Titrations … this case we can use Ag2CrO4, because a solution of CrO42- of moles of the other, and the molar concentration or the volume of added solution can be of a silver salt, say silver nitrate, whose concentration is known. is, pX = -log c(X) or pX = -log a(X). Of Pharmacy 2. The titration is carried out in an acidic solution to prevent the precipitation of Fe3+ as Fe(OH)3. so at the start of the titration [Ag+] = 1.76 x 10-10/1 x 10-2 Example – To determine the concentration of chloride ion in a certain solution we can titrate this solution with silver nitrate solution (whose concentration is known). The purpose of titration is to determine concentration of the unknown substance (Fromm, 1997). The reaction in this case is, \[\text{Ag}^+(aq) + \text{Cl}^-(aq) \rightleftharpoons \text{AgCl}(s) \nonumber\], Because the reaction’s equilibrium constant is so large, \[K = (K_\text{sp})^{-1} = (1.8 \times 10^{-10})^{-1} = 5.6 \times 10^9 \nonumber\]. To compensate for this positive determinate error, an analyte-free reagent blank is analyzed to determine the volume of titrant needed to affect a change in the indicator’s color. Ag+ + Cl− Image AgCl (ppt.) Because this equation has two unknowns—g KCl and g NaBr—we need another equation that includes both unknowns. For example, in forming a precipitate of Ag2CrO4, each mole of \(\text{CrO}_4^{2-}\) reacts with two moles of Ag+. If the pH is too acidic, chromate is present as \(\text{HCrO}_4^{-}\) instead of \(\text{CrO}_4^{2-}\), and the Ag2CrO4 end point is delayed. Finally, we complete our sketch by drawing a smooth curve that connects the three straight-line segments (Figure \(\PageIndex{2}\)e). Back titration is a titration done in reverse; instead of titrating the original sample, a known excess of standard reagent is added to the solution, and the excess is titrated. To find the moles of titrant reacting with the sample, we first need to correct for the reagent blank; thus, \[V_\text{Ag} = 36.85 \text{ mL} - 0.71 \text{ mL} = 36.14 \text{ mL} \nonumber\], \[(0.1120 \text{ M})(0.03614 \text{ L}) = 4.048 \times 10^{-3} \text{ mol AgNO}_3 \nonumber\], Titrating with AgNO3 produces a precipitate of AgCl and AgBr. is first slowly reduced by the precipitation of AgCl as a consequence of the continuous One of the earliest precipitation titrations—developed at the end of the eighteenth century—was the analysis of K 2 CO 3 and K 2 SO 4 in potash. we may assume that Ag+ and Cl– react completely. In First, the sample to be … 7/29/2019 09 Precipitation Titration. Report the %w/w I– in the sample. Worked Example: Precipitation Titration of KCl (aq) with AgNO 3(aq). … The precipitate formed is the less soluble compound. AgNO3 + NaCl → AgCl + NaNO3 AgNO3 + NH4CNS → AgCNS + NH4NO3 You can review the results of that calculation in Table 9.18 and Figure 9.43. 7. A precipitation reaction is a chemical reaction that occurs in aqueous solution and form precipitates. What voltage reading would be observed after 65.0 mL? The indicator that we used was K2CrO4 that gave a reddish brown precipitate. In a precipitation titration, the stoichiometric reaction is a reaction which produces in solution a slightly soluble salt that precipitates out. The pH also must be less than 10 to avoid the precipitation of silver hydroxide. The scale of operations, accuracy, precision, sensitivity, time, and cost of a precipitation titration is similar to those described elsewhere in this chapter for acid–base, complexation, and redox titrations. addition of silver ion. The titration … separable solid compounds form during the course of the reaction. The basis of this titration is on the precipitate formation. Precipitation titration Nirmal raj marasine pharmacist cmc 8/26/2015 1 2. The reaction occurs by the formation of a solid precipitate at the bottom of the flask. = [Ksp] = 1.76 x 10-1, [Ag+] = 1.33 x 10-5 and One of the earliest precipitation titrations—developed at the end of the eighteenth century—was the analysis of K2CO3 and K2SO4 in potash. Precipitation Reaction. in solution a slightly soluble salt that precipitates out. image/svg+xml. Next, we draw a straight line through each pair of points, extending them through the vertical line that represents the equivalence point’s volume (Figure \(\PageIndex{2}\)d). Again, the calculations are straightforward. Since by the definition of molarity n = cV, Precipitation titrations are mainly based on the formation of the precipitate by the reaction of the sample with precipitating agents. When the silver(I) has been precipitated as white silver thiocyanate, the first excess of titrant and the iron(III) indicator react and form a soluble red complex. We call this type of titration a precipitation titration. This kind of titration is based on precipitation reactions, i.e. A precipitation titration curve follows the change in either the titrand’s or the titrant’s concentration as a function of the titrant’s volume. Ionic. After the equivalence point, the titrant is in excess. Figure \(\PageIndex{2}\)a shows the result of this first step in our sketch. Other articles where Precipitation titration is discussed: titration: Precipitation titrations may be illustrated by the example of the determination of chloride content of a sample by titration with silver nitrate, which precipitates the chloride in the form of silver chloride. We bring two reacting substances into contact in precipitationtitration. equivalence point. separable solid compounds form during the course of the reaction. The results of a precipitation titration experiment can be used to determine the concentration of halide ions in water samples as shown in the steps below: For the precipitation reaction: Ag + (aq) + X-(aq) → AgX (s) Volume of AgNO 3(aq) added is recorded … An … = 1.76 x 10-8 and no precipitate of Ag2CrO4 can form. 4) Precipitation titration curve is influenced by the conc. PRECIPITATION TITRATION. PRECIPITIMETRY. We call this type of titration a precipitation titration. This change in the indicator’s color signals the end point. Karl Friedrich Mohr Jacob Volhard Kazimierz Fajans. At best, this is a cumbersome method for detecting a titration’s end point. ion through the common ion effect. Worked example: Determining solute concentration by acid-base titration. Precipitation titration is a special type of titrimetric procedure, which involves the formation of precipitates during the course of titration. The titrating agent, therefore, has to … Dichlorofluoroscein now adsorbs to the precipitate’s surface where its color is pink. The %w/w Ag in the alloy is, \[\frac{1.265 \text{ g Ag}}{1.963 \text{ g sample}} \times 100 = 64.44 \text{% w/w Ag} \nonumber\]. A 0.3172-g sample is dissolved in 50 mL of water and titrated to the Ag2CrO4 end point, requiring 36.85 mL of 0.1120 M AgNO3. Precipitation titrations are based upon reactions that yield ionic compounds of limited solubility. As we did for other titrations, we first show how to calculate the titration curve and then demonstrate how we can sketch a reasonable approximation of the titration curve. Since the chemical reaction is one silver ion to one chloride ion, we Legal. when KSP value is small the titration curve is perfect . The molar concentration of either chloride ion or silver ion will change over several The %w/w I– in a 0.6712-g sample is determined by a Volhard titration. Note You can use this to monitor Cl- ! A blank titration requires 0.71 mL of titrant to reach the same end point. Before the equivalence point, Cl– is present in excess and pCl is determined by the concentration of unreacted Cl–. They are in many ways simpler than gravimetric methods. A Presentation On Precipitation Titration Dept. The titration is continued till the last drop of the analyte is consumed. precipitation is complete and the amount of silver ion that has been added is equivalent The titration is carried out in acidic solution. titrant is added, and both the addition and the reaction continue until one of the The importance of precipitation titrimetry as an analytical method reached its zenith in the nineteenth century when several methods were developed for determining Ag+ and halide ions. Analyte Cl-Cl-Cl-Titrant AgNO3AgNO3 (excess) KSCN (back-titration… range. Before precipitation titrimetry became practical, better methods for identifying the end point were necessary. It is inconvenient to the point of being impractical to plot, or even to compare, the Precipitation Titrations 146 4. no precipitate will form. The molar concentration of the unknown solution is calculated as Precipitation titration is used in many industries. The titration’s end point is the formation of the reddish-colored Fe(SCN)2+ complex. titration is known. during the reaction a salt is precipitated as the titration is completed. The titrant react with the analyte forming an insoluble material and the titration … The Volhard method was first published in 1874 by Jacob Volhard. The term "equivalent" is used orders of magnitude during the course of a titration, as the concentration of chloride ion To determine the chloride ion concentration in a solution, we performed precipitation titration by Mohr method in this experiment. … Precipitation titration. The LibreTexts libraries are Powered by MindTouch® and are supported by the Department of Education Open Textbook Pilot Project, the UC Davis Office of the Provost, the UC Davis Library, the California State University Affordable Learning Solutions Program, and Merlot. The precipitate formed is the less soluble compound. Precipitation titrations are based on reactions that yield ionic compounds of limited solubility. Example: When use of the solution of silver nitrate takes place to a solution of ammonium thiocyanate or sodium chloride. A comparison of our sketch to the exact titration curve (Figure \(\PageIndex{2}\)f) shows that they are in close agreement. Before the equivalence point the titrand, Cl–, is in excess. or a pAg of 7.82. Because this represents 1⁄4 of the total solution, there are \(0.3162 \times 4\) or 1.265 g Ag in the alloy. Precipitation Titration A special type of titremetric procedure involves the formation of precipitates during the course of titration.