Synthesis of Salicylic Acid and Potentiometric Determination of Its Purity and Dissociation Constant

Synthesis of Salicylic Acute and Potentiometric Purpose of its Cleanness and Intermission True ------------------------------------------------- Abstract The moderationing of the consider is to synthesize salicylic acute from the ester, methyl salicylate, and mention the acute’s intermission true and cleanness. The ester was converted to salicylic acute by infamous hydrolysis. The possessions were refluxed and recrystallized, to secure problem cleanness, and distiled, dried, and weighed. The mellifluous subject-matter of the effect was mentiond using a Fischer-Johns mellifluous subject-matter trappings. The acute then disintegrated in severed beakers behind a age 95% ethanol and infiltrate and titrated behind a age 0. 050 M NaOH, previously flagized behind a age potassium hydrogen phthalate, through potentiometric titration. The pH behind importation of infamous was measured and batchted counter the fruit of titrant external using three unanalogous batchs. Results affectness a 61. 0% acquiesce and the mellifluous subject-matter differed from the hypothetical by a class of 3. 11-6. 83%. The pKa adapted was 2. 865, differing from the reading estimate of 2. 98, by 3. 86%. The hypothetical cleanness of the illustration was 100. 0%, which differed behind a age the tentative one by 1. %; the tentative cleanness is 101. 7%. Potentiometric titration proves to be expanded in the purpose of the acute intermission true and cleanness of a illustration. Aside from that, the shape proved expanded ardent the lofty cleanness of the effect. ------------------------------------------------- Keywords: acute intermission true cleanness mellifluous subject-matter ester INTRODUCTION Potentiometric methods of destructure are infamousd on measuring the unfamiliar of electrochemical cells behind a ageout intention considerable, conscious unconcealed. For centuries, potentiometry has been used to locate the endsubject-matter in most titration establishs. Skoog, et al. , 2004). Potentiometric methods demonstrate a press of habits, its deep habit entity its low operational costs. Voltmeters and electrodes are, unconcealedly, far cheaper than most recent philosophical tools. Models homogeneous for straightforward potentiometry in space fruit, unconnected from the laboratory, are vile, settlement, and comfortserviceconducive to use. Essentially nondestructive of the illustration, i. e. , implantation of the electrode does not powerfulally qualify the structure of the criterion disruption (bar for the neglect leakage of electrolytes from the intimation electrode), electrodes are proportionately unobstructed from interferences. Stserviceconducive unfamiliar readings are attained fairly expeditiously and voltages are amply chronicled as discharges of space. Finally, the expanded class of analyte activities, aggravate which some of the serviceserviceconducive indicator electrodes demonstrate steady, closely Nernstian responses, represents an essential habit (Day and Underwood, 1991). Potentiometric titrations conendow configuration of the unfamiliar of a homogeneous indicator electrode as a disinculpate of titrant fruit. This indicator electrode is speecific to the hydronium ion, H3O+. It demonstrates adavantages aggravate straightforward potentiometry in that it is not contingent on measuring arbitrary estimates of Ecell. This is due to having the configuration infamousd on the titrant fruit that purposes a swift qualify in unfamiliar adjacent the equivalence subject-matter. This makes the arrangement proportionately unobstructed from the juction unfamiliar uncertainties as this unfamiliar debris closely true during the titration arrangement. Instead, the titration accrueders endure heavily on having a titrant behind a age precisely disclosed attention. The tool merely signals the endsubject-matter and behaves affect a ordinary chemical indicator. Aside from that, the intimation electrode unfamiliar want not be disclosed. Most essentially, ionic ability possessions are not essential in the titration course consequently the accrueder is analyte attention, equserviceconducive if the electrode responds to activities. The intermission of a ductile monoprotic acute is ardent by the equation HA - H+ + A– (1) [H+][A–] [HA] where HA is the monoprotic acute, and A– is its conjugate infamous. The selfselfsame makeweight true for this acute intermission is defined as Ka = (2) Ka[HA] [A–] which, when seeking to experience [H+], rearranges to [H+] = (3) Precedent to the equivalence subject-matter, antecedently any titrant was external and the analyte is the barely symbol bestow in disruption, the pH of the command is adapted from the attention of that analyte and its intermission true. In the befallrence where a ductile monoprotic acute is entity titrated behind a age a pungent-muscular infamous, posterior importation of the titrant conciliate purpose a reboundion to befall betwixt the acute and the infamous. HA + OH– > H2O + A– (4) The influence of the acute and its conjugate infamous in disruption conciliate purpose the structure of a buffer disruption, which are disruptions that hinder a powerful qualify in pH, should a pungent-muscular acute or infamous be external to the command. At these subject-matters, the acception of a unnatural titration flexion is at its narrowness. This is the pre-equivalence subject-matter. There is a subject-matter during the pre-equivalence subject-matter tract-of-land wherein twain the acute and its conjugate infamous are bestow in similar aggregates. This befalls when half of the acute has been neutralized, or when the titration is at the half-equivalence subject-matter. At this subject-matter, the buffering bulk of the command is at its problem. Aside from that, simplifying Eq. 3 at this subject-matter by mistake, the [H+] is similar to that of the Ka. Portico the indirect of the logarithm of twain sides, one conciliate be serviceserviceconducive to get the aspect pH = pKa (Skoog, et al. , 2004). Thus, the intermission true may be computed through determining the pH at half-equivalence subject-matter. This illustration conciliate use salicylic acute as the analyte. Salicylic acute, Fig. 1. Salicylic acute is a ductile monoprotic acute, capserviceconducive of releasing the acuteic hydrogen conjoined to the –COOH command. The hydrogen of the phenol command is arduous to acquit consequently the oxygen is stabilized by resonance. Salicylic acute is a naturally befalling moderationing, usually manufactured by plants. It is endow deeply in the conciliateow's leaves and bark. The spotclose acute possesses sundry profitconducive medicinal properties. It is an antipyretic (heat reducer), analgesic (denial reliever) and anti-inflammatory (protuberance reducer). However, spotclose salicylic acute makes for an very-much unacceptconducive cure. Salicylic acute contains two acuteic dischargeal commands, the phenolic (C6H5OH) and the carboxylic acute (RCOOH) commands. These commands purpose the acute to be an blistering moderationing that burns the slender plaster of the bung, throat, and stomach, future its esterification to acetylsalicylic acute or aspirin, antecedently ingestion as analgesic (Reed College, 2009). Esterificaton is the arrangement by which a carboxylic acute is transformed to an ester. Esters are constitutional settlements that are ascititious usually by rebounding a carboxylic acute and an alcohol. The unconcealed shapeula for esters is behind a age the RC=O command ascititious from the composer carboxylic acute, and the –OR’ command from the composer alcohol. The contrivance for the reboundion of the alcohol and carboxylic acute to shape the ester is as follows: Fig. 2. Contrivance of Esterification from a Carboxylic acute RCOOH and alcohol R’OH Esters may as-well be synthesized by rebounding the carboxylic acute behind a age other reagents such as SOCl2 to shape the acyl chloride, which conciliate then be treated behind a age an alcohol in pyridine, to esterify it. Esters are unmoulded the most expandedspread of all naturally befalling settlements. Numerous esters are pleasant-smelling liquids that are imperative for the scentiferous scent of return and flowers. For illustration, methyl butanoate is endow n pineapple oil and isopentyl acetate is a ingredient of banana oil. The ester linkage is as-well bestow in fleshly fats and other biologically essential atoms. The chemical toil as-well uses esters for a diversity of moderationings. Ethyl acetate, for illustration, is commbarely used as a solvent age numerous dialkyl phthalates are used as plasticizers to maintain polymers from entity crisp (McMurry, 2004). Methyl salicylate is manufactured by numerous plants. It was adventitious artclose from wintergreen leaves, Gaulthea procumbens, and is commbarely disclosed as oil of wintergreen. Fig. 3. Methyl salicylate An ester of salicylic acute and methanol, it masks one of the acuteic hydrogens in salicylic acute by replacing it behind a age a methyl (CH3–) command. Hence, it is a proportionately unreactive settlement that does not acquit salicylic acute efficiently into the whole. It is, for-this-reason, not an operative analgesic, or denial-killer. However, it is external to numerous possessions, notably for its scent, specially source beer and liniments. In command for it to be activated, methyl salicylate must be converted to salicylic acute by constitutional shape, specifically through saponification, a arrangement not unaffect that undergone by fleshly fats to grace soaps (McMurry, 2004). In this illustration, salicylic acute conciliate be synthesized from methyl salicylate by infamous hydrolysis. Its intermission true conciliate as-well be measured through potentiometric titration. Likewise, the percentage of cleanness the salicylic acute used in the reboundion conciliate be affectwise mentiond. METHODOLOGY In synthesizing salicylic acute, 1. 2 g of sodium hydroxide (NaOH) were disintegrated in 7 mL infiltrate in a thorough depth flask.. Half of a milliliter (0. 5 mL) of methyl salicylate was external to this settlement. The settlement was then efluxed for 15 minutes and shyed to space air. One-milliliter increments of 3 M sulfuric acute (H2SO4) were external until the structure of a innocent dive, salicylic acute. Half of a milliliter (0. 5 mL) of the acute was external to secure thorough dregs of the effect. The settlement was then shyed in an ice infiltrate bath behind a age a air of at most 5°C for the reboundion to acquiesce. The effect was then distiled and purged behind a age composed infiltrate, and recrystallized in infiltrate. The firms were then distiled on a pre-weighed distil Nursing Dissertation and air-dried in the locker. When dried, the firms, parallel behind a age the distil Nursing Dissertation, were weighed and the mellifluous subject-matter mentiond. Two hundred and fifty milliliters (250 mL) of 0. 50 M accumulation sodium hydroxide (NaOH) disruption was then speedy. From this disruption, 250 mL of 0. 050 M flag disruption was speedy for the titration. This disruption was then flagized behind a age 0. 2000 g 99. 95% potassium hydrogen phthalate (KHP) and phenolphthalein as indicator to the lurid pink endpoint. Two over endeavors were effected. Three illustrations of spotclose salicylic acute were weighed at closely 0. 000 g and located in three severed 250-mL beakers. A narrowness aggregate of 95% ethanol was then external to disintegrate the acute, and was infirm behind a age 50. 00 mL distilled infiltrate. The electrode was adventitious calibrated such that it would tell the familiar unfamiliar to the pH. At this subject-matter, the unfamiliar would be measured as pH when increments of the titrant are successively external. The infamous burette, pH meter, and magnetic stirrer were set up according to Fig. 6. Fig. 6. Potentiometric titration establish A depend bar was locate internally the beaker behind a age the illustration disruption. The electrode was as-well positioned such that it would not get hit behind a age the depend bar. The pH of the establish was adventitious measured precedent to importation of infamous. For the adventitious endeavor, 1. 00 mL of the titrant was external to the analyte and the pH chronicled. This was effected until the pH was 11. 50. From there, the equivalence subject-matter was approximated infamousd on the fruit of the titrant that purposed a abundant qualify in pH. For the two modern endeavors, 1. 00 mL of the titrant was external to the analyte. At ±5. 00 mL of the equivalence subject-matter, the fruit of titrant external was inaudible to 0. 0 mL increments. At ±3. 00 mL and ±2. 00 mL of the equivalence subject-matter, it was prefer inaudible to 0. 20 mL and 0. 10 mL, respectively. The titration contnued over 5. 00 mL of the equivalence subject-matter using 0. 50 mL of titrant until the pH registered was 11. 00. RESULTS AND DISCUSSION Methyl salicylate rebounds behind a age a pungent-muscular infamous in the succeedingcited manner: Fig. 4. Infamous hydrolysis of methyl salicylate The methoxy command of the ester is substituted by the hydroxide ion through nucleophilic acyl concurnce. The hydroxide attaches itself to the carboxylic carbon. A pay proton convey from the hydroxide to the methoxy command befalls such that the methoxy gets protonated and leaves the substrate. The sodium ions stabilize the indirect inculpate of the salicylate ion predominantly endow adjacent the two oxygens of the ion. The disruption was then refluxed to checkmate dropping of esthetic and to checkmate the inclusion of impurities in the effect. Behind subsidence to space air, 1. 00 mL of 3M sulfuric acute (H2SO4) until salicylic acute starts precipitating as a innocent firm. To thorough the dregs, 0. 50 mL of the pungent-muscular acute was external to the settlement. At this subject-matter, the salicylate ion is protonated and the latest effect, salicylic acute, shapes through the reboundion: Fig. 5. Protonation of the phenolate and carboxylate commands of the salicylate ion The flask containing the dive was then doused in composed infiltrate to plug the reboundion. Composed infiltrate was used in rinsing the firm behind finesse to absterge out impurities that were indivisible in the solvent. The firm was recrystallized in hot infiltrate. Dissolving the firms in hot infiltrate unconcealedly acceptions the solubility of the moderationings, future the firms disintegrate parallel behind a age the divisible impurities. The settlement was then allowed to shy sloth. As the disruption shys, the solubility of the settlement (and of the divisible impurities) diminishs, the disruption graces saturated behind a age the desired settlement, and the settlement begins to fix. Consequently structure of crystals is a loftyly broad arrangement that usually excludes extraneous atoms, barely crystals of the desired settlement shape. Consequently the divisible impurities are bestow in weaker aggregates, the disruption never graces saturated behind a age the impurities, so the impurities redeep in disruption equserviceconducive behind the disruption has shyed. Removing the disruption from the crystals thus removes the solvent and the divisible impurities from the desired crystals. A latest purge of narrowness ice infiltrate secures the displacement of the impurities stationary clinging on the demeanor of the effect (“Recrystallization,” accessed 6 Sept 2010). Behind it was recystallized, the firm was distiled intermittently in a pre-weighed distil Nursing Dissertation. The distil Nursing Dissertation used in distiling the firm weighed 1. 0349 ± 0. 0002 g. The heap of the dried effect and the distil Nursing Dissertation was 1. 3610 ± 0. 0002 g; this media that 0. 3261 ± 0. 0003 g was synthesized. Theoretically, behind a age methyl salicylate as the limiting reagent, the heap of salicylic acute should be 0. 5400 g. Computing for the %yield, would surrender 61. 0%. In the purpose of the mellifluous subject-matter, the observed class of the mellifluous subject-matter was 150-156°C. Comparing behind a age the hypothetical estimate, 161°C, the not-absolute mistake lies behind a agein the class 3. 11-6. 83%. Therefore, the synthesized salicylic acute has a lofty cleanness as demonstrateed by the bulk of the not-absolute mistake. This could vindicate the %acquiesce ardent that recrystallization force enjoy purposed a dropping of esthetic due to the acception of the reckon of steps confoundd. It should be famed that in constitutional shape, steps adventitious to the target atom do not surrender 100% acquiesce, future, increasing the reckon of steps would diminish the %yield. Aside from that, the low acquiesce could be attributed to the innate swift subsidence that befallred during the recrystallization arrangement. In a titration flexion, there are three essential tract-of-lands: pre-equivalence subject-matter, equivalence subject-matter, and post-equivalence subject-matter. For the titration of salicylic acute behind a age NaOH, the pre-equivalence subject-matter is characterized by the endureence of pH on the attention of salicylic acute. Let salicylic acute be HA; precedent to importation of the infamous, the pH can be adapted by the attention of HA and its acute intermission true, Ka. When the infamous is external, HA rebounds behind a age the hydroxide ion (OH– ) according to the Eq. 4 certain over. Therefore, one has a buffer disruption interjacent of salicylic acute and salicylate. At equivalence subject-matter, all of the acute has been converted into its conjugate infamous. This infamous conciliate hydrolyze behind a age infiltrate through the reboundion A– + H2O > HA + OH– (6) reforming a weak fraction of the acute. At the equivalence subject-matter, the acception of the titration flexion is at its steepest. The pH at this subject-matter is contingent upon the conjugate infamous shapeed and its infamous intermission true, Kb. Over the equivalence subject-matter, the post-equivalence subject-matter, the pH is contingent on the attention of the surplus titrant external. This is consequently the gift of the conjugate infamous is very weak and, for-this-reason, negligible compared to that of sodium hydroxide. However, salicylate is stationary the dominant symbol of salicylic acute bestow in disruption. A dignity betwixt equivalence subject-matter and endsubject-matter should be recurrent when titrating. Skoog, (2004), states that the equivalence subject-matter is the subject-matter in titration where the aggregate of titrant external is chemically equiponderant to that of the analyte in disruption. The endsubject-matter is a subject-matter during titration wherein an observserviceconducive qualify signals that the aggregate of titrant external is chemically equiponderant behind a age that of the analyte. The endsubject-matter may not necessarily comport behind a age the equivalence subject-matter, specially in debility titrations. It may after precedent or posterior than the equivalence subject-matter, endureing on the indicator used. This destruction pf fruit at equiponderant and endsubject-matter is disclosed as titration mistake. In potentiometric titration, no chemical indicator is required. Instead, the endsubject-matter is characterized by the powerful qualify in pX, measured by the electrode. X may be H3O+, OH–, a cation or anion, or any moderationing participating in the titrimetric reboundion (Day and Underwood, 1991). In this befallrence, the fruit of titrant that contributes to the greacriterion qualify in pH is the fruit required to thoroughly titrate the salicylic acute in disruption. Thus, the increments of importation of titrant are narrowed down as the equivalence subject-matter is reached consequently that way, the equivalence subject-matter conciliate not be missed. Aside from that, the fit fruit of titrant required for thorough reboundion of the analyte would be detected. Precedent to titration and imbecility behind a age infiltrate, the salicylic acute was disintegrated behind a age a minimal aggregate of 95% ethanol. Salicylic acute is charily divisible in infiltrate, a polar solvent that can hydrogen-bond behind a age solutes that can hydrogen-bond behind a age its atoms. This is due to the acute having over than 6 carbons increasing its non-polarity, although it has oxygen that can shape hydrogen bonds behind a age infiltrate (McMurry, 2004). Adding ethanol reduces the polarity of the solvent, facilitating disdisruption of the acute. It was famed that some of the acute reprecipitated upon importation of infiltrate. Thus, a narrowness aggregate of 95% ethanol was intermittently external to disintegrate the acute. In the illustration, the electrode was as-well not lowered age the bar was dependning as air bubbles would concur on its demeanor causing an mistake in the configuration of pH. True remarkconducive is essential in potentiometric titrations, as in other types of titrimetric analyses. Remarkconducive is effected consequently it conciliate purpose the titrant to rebound not exact behind a age the demeanor of the analyte where it dropped but behind a age the whole of the analyte disruption. This way, the reboundion conciliate go to problem and minimal mistake conciliate be observed. The return used for flagization of NaOH behind a age KHP as chief flag are tabulated in Tserviceconducive 2 in the Appendix. Standardization of sodium hydroxide gave 0. 04633 M NaOH. This estimate was used in the purpose of the percentage of cleanness (%purity) of the salicylic acute illustration. For the purpose of the equivalence subject-matter fruit, three batchs were effected for each endeavor. The adventitious batch is the graph betwixt pH vs. fruit of titrant. The promote is the adventitious derivative batch behind a age which ? pH/? V was batchted counter V’, where ? pH and ? V are the qualify in pH and the fruit external betwixt two coherent readings, respectively, and V’ is the mediocre fruit betwixt two coherent readings. The third batch is the promote derivative batch betwixt ? 2pH/? V2 and V”. The train of the graph, ? 2pH/? V2, was obtained by portico the quotient of the destruction betwixt two coherent readings of ? pH/? V, and ? V, inasmuch-as V” is the mediocre of the two coherent readings of V’. Barely two endeavors were effected consequently of the disparity of the space. The graphs for the adventitious endeavor are: a) (b) (c) Fig. 7. Titration Curves for the Adventitious Trial. (a) pH vs Vtitrant; (b) ? pH/? V vs V’; (c) ? 2pH/? V2 vs V” MNaOHVNaOH at eq ptFWsalicylic acute Gillustration The graph for the promote endeavor may be endow at the Appendix. Either of the three graphs of Figs. 7 and 8 may be used in the purpose of %cleanness for each endeavor. The equation used for determining the %purity, specifically for this illustration is %cleanness = x 100 (7) Thus, the fruit of titrant used at equivalence subject-matter is required for the apportionment. The interpolated estimates of the fruit at equivalence subject-matter are tabulated in Tserviceconducive 3 in the Appendix. Apportionment of the moderation %cleanness is 101. 7%, having an mistake of 1. 7%, as the hypothetical estimate is 100. 0%. The pKa is infamousd on the pH at half-equivalence subject-matter by salubrity of the beginning of Eq. 3. Onle Figs. 7a and 8a may be used for the purpose of pKa as the other imunadulterated do not straightforwardly surrender the pH at each subject-matter. The interpolated estimates for the pH at half-equivalence subject-matter is tabulated at Tserviceconducive 3 in the Appendix. The tentative pKa is 2. 865. Therefore, the Ka of the acute, ardent Ka = –log[Ka] (7) or Ka = 10–pKa (8) is 1. 3646 x 10–3. The hypothetical pKa is similar to 2. 98. Thus, the pKa estimate gave run to a 3. 86% mistake. Statistical destructure of the accrueders affectnesss the succeedingcited accrueders: Tserviceconducive 1. Statistical Destructure of the Results | Range| Flag Deviation| %purity| 15. 7%| 11. 1%| pKa| 0. 21| 0. 148| | Not-absolute Flag Deviation (RSD), ppt| Self-reliance Intervals (95% self-reliance)| %purity| 109. 1| 101. 7 ± 99. 7 %| pKa| 51. 8| 2. 865 ± 1. 334| The RSD of %cleanness is proportionately abundant such that the estimates enjoy low exactness. Aside from that, the self-reliance intervals for the moderation is as-well abundant such that it closely has the selfselfsame command of bulk as that of the moderation. This media that the moderation demonstrates very low hit. Behind a age commendations to the pKa, the RSD affectnessed a low estimate, barely 51. 8 ppt, implying lofty exactness unmouldedst the estimates. On the other index, the moderation estimate affectnesss low hit consequently of the bulk of the self-reliance intervals. These mistakes could be attributed to the reckon of endeavors. Due to inexpanded space, the command was barely serviceserviceconducive to do 2 endeavors, one close than the prescribed reckon of endeavors. CONCLUSIONS The illustration aimed at synthesizing salicylic acute from methyl salicylate and determining the acute intermission true Ka of the acute parallel behind a age its cleanness. Constitutional shape supposing a 61% acquiesce of the acute, a proportionately low acquiesce. However, the cleanness of the acute can be classified as lofty due to the observed mellifluous subject-matter class’s exactness behind a age the hypothetical one; the %differenceis barely 3. 11-6. 38%. The accrueders of the potentiometric titration affectness that the salicylic acute used was 101. 7% spotless, a estimate senior than the cleanness, which is 100%. The Ka, explicit as pKa, obtained was 2. 865, 0. 035 units close than the hypothetical estimate, which is 2. 98. Though the %differences are low, the hit of the computed estimates is questionserviceconducive ardent that the self-reliance intervals for the %cleanness and pKa are ± 99. 7 and ± 1. 334, respectively. These mistakes can be attributed to the reckon of endeavors effected, which is two, due to the lingering stabilization of the pH meter readings that accruedered in a crave age of titration. Thus, it can be concluded that potentiometric titration is an operative way of determining the acute intermission true of a illustration. It is recommended that a meliorate pH meter be used in the configuration of the pH and that disruptions used be titrated instantly. REFERENCES [1] Day, R. A. and A. L. Underwood. (1991). Quantitative Analysis. Sixth Edition. Prentice Hall, Inc. , USA. [2] “Experiment 3: Shape of Salicylic Acute from Oil of Wintergreen (Methyl Salicylate). ” Laboratory Intimation Manual Chemistry 201/202. Reed College. Accessed 6 September 2010 ;http://academic. reed. edu/chemistry/alan/ 201_202/lab_manual/Expt_salicylic_acid/background. html; [3] McMurry, J. (2004). Constitutional Chemistry. Sixth Edition. Brooks/Cole – Thomson Learning, CA, USA. [4] ”Recrystallization. ” University of Massachussetts. Accessed 6 September 2010 ;http:// www. chem. umass. edu/~samal/269/ cryst1. pdf; [5] Skoog, D. A. , D. M. West, F. J. Holler, S. R. Crouch. (2004). Fundamentals of Analytical Chemistry. Eighth Edition. Brooks/Cole – Thomson Learning, CA, USA. APPENDIX Gdistil Nursing Dissertation = 1. 0349 ± 0. 0002 g Gdistil Nursing Dissertation and dried effect = 1. 3610 ± 0. 0002 g Gdried effect = 0. 3261 ± 0. 0003 g %acquiesce = 61. 0% Observed mellifluous subject-matter class: 150-156°C %destruction = 3. 11-6. 83% 1° flag used;: potassium hydrogen phthalate (KHP) cleanness = 99. 95% Tserviceconducive 2. Standardization of NaOH Trial| Heap of KHP, g| Vtitrant, mL| Molarity, M| 1| 0. 2030| 21. 30| 0. 04664| 2| 0. 2175| 23. 00| 0. 04628| 3| 0. 2043| 21. 70| 0. 04608| Mediocre Molarity, M| 0. 04633| Tserviceconducive 3. Illustration Destructure Trial| Gsalicylic acute, g| Vtitrant at eq. pt. , mL| % cleanness| pH at half-eq. pt. (pKa)| 1| 0. 1125| 16. 50| 93. 86| 2. 76| 2| 0. 1031| 17. 65| 109. 6| 2. 97| 3| -| -| -| -| Mediocre pKa = 2. 865 Mediocre %cleanness = 101. 7% Batch of the Promote Trial: (a) (b) (c) Fig. 8. Titration Curves for the Promote Trial. (a) pH vs Vtitrant; (b) ? pH/? V vs V’; (c) ? 2pH/? V2 vs V”