Acetic acid titration with sodium

Titration profile of acetic acid (CH3COOH) with sodium hydroxide (NaOH). Maximum buffering capacity is at pH = pK, at which point minimal change in pH occurs upon addition of acid or base. 

The titration curve for 100 mL of 0.1 M acetic acid titrated with 0.1 M sodium hydroxide is shown in Figure 8.5. The neutralization reaction is... 

Procedure (iodometric method). Weigh out accurately about 5.0 g of the bleaching powder into a clean glass mortar. Add a little water, and rub the mixture to a smooth paste. Add a little more water, triturate with the pestle, allow the mixture to settle, and pour off the milky liquid into a 500 mL graduated flask. Grind the residue with a little more water, and repeat the operation until the whole of the sample has been transferred to the flask either in solution or in a state of very fine suspension, and the mortar washed quite clean. The flask is then filled to the mark with distilled water, well shaken, and 50.0 mL of the turbid liquid immediately withdrawn with a pipette. This is transferred to a 250 mL conical flask, 25 mL of water added, followed by 2 g of iodate-free potassium iodide (or 20 mL of a 10 per cent solution) and 10 mL of glacial acetic acid. Titrate the liberated iodine with standard 0.1M sodium thiosulphate. 

Soliman and Belal investigated argentimetric (67,68) and mercurimetric (69) methods. Hydralazine precipitates silver from ammoniacal silver nitrate solution. The silver is dissolved with hot nitric acid and titrated with ammonium thiocyanate solution. Alternatively, mercury is precipitated from alkaline potassium mercuric iodide solution. The precipitated mercury is dissolved by adding excess standard iodine solution. The excess iodine is back-titrated with sodium thiosulfate solution after acidifying with acetic acid. 

Titration reaction (the acetic and hydrochloric acids are titrated with sodium hydroxide). 

The substance is hydrolysed by boiling under reflux with 50 per cent sulphuric acid and the acetic acid or benzoic acid produced is distilled in steam and titrated with sodium hydroxide solution, using phenolphthalein as indicator. 

The amount of hydroxyl group present is found by titrating the resulting acetic acid (CH3COOH) with standard sodium hydroxide, as in (1). 

Add 5 ml of an approximately 0.5 m ethereal solution of lithium aluminium hydride to 50 ml of a standardised approximately 0.2 m iodine solution in benzene. Shake the solution gently and allow to stand for 5 minutes, add 50ml of distilled water followed by about 2 ml of glacial acetic acid. Titrate the excess of iodine with a standardised 0.2 m solution of sodium thiosulphate using starch solution in the final stages to determine the end-point. 

Effluent-gas Analysis.4 This method of analysis gives an estimate both of the chlorine (IV) oxide produced and of the unreacted chlorine present in the effluent-gas mixture. The gas is collected in an opaque 600-ml. Hempel tube it is then absorbed in a neutral 10% solution of potassium iodide. Starch indicator is added to this solution or to an aliquot, which is then titrated with 0.1 AT sodium thiosulfate solution (titration A). The amount of sodium thiosulfate used is equivalent to all the chlorine gas in the sample plus one-fifth of the chlorine(IV) oxide. The solution is then acidified with an excess of 30% acetic acid, causing a second release of iodine, which is then titrated with sodium thiosulfate solution (titration B). The amount of sodium thiosulfate used in titration B is equivalent to four-fifths of the chlorine (IV) oxide in the sample. The equations for the reactions involved are shown below.4... 

Determination of the Hydroperoxide. Glacial acetic acid (30 ml.) containing 0.0005% ferric chloride hexahydrate and 5 ml. saturated potassium iodide solution was added to an aliquot of the hydroperoxide solution which had been flushed with nitrogen. The mixture was stored in the dark for 10 minutes, diluted with water (50 ml.), and the liberated iodine was titrated with sodium thiosulfate solution using starch as indicator. 

It was found impossible to measure the rate of decomposition by the evolution of gases because the release of these gas bubbles is very slow and erratic. The course of the reaction was followed by analyzing samples for the ammonium ion. Small amounts of the decomposing amalgam were forced through a capillary tube into a chilled solution of an iodate. The ammonium reacted with iodate ion to give iodide ion. The solution was then acidified with acetic acid and the iodine distilled out, collected and titrated with sodium thiosulfate. The method was checked with samples... 

In general, the aliphatic hydroxyl content of a lignin preparation is determined by subtraction of the phenolic hydroxyl content (see Chap. 7.2) from the total hydroxyl content of the lignin. The total hydroxyl content of lignin (partial structure H) can be determined by acetylation with acetic anhydride-pyridine reagent (10) followed by saponification of the acetate (partial structure 12) and titration of the resulting acetic acid (14) with a standard 0.05 N sodium hydroxide solution (Roth 1953). 

Kenyon and associates have compared the uronic acid values obtained by the above method with the carboxyl values obtained by the calcium acetate method. " In the latter procedure, a calcium acetate solution is added to cellulose which contains free carboxyl groups. A replacement reaction takes place, and the acetic acid liberated is titrated with sodium... 

The deterioration of petroleum wax results in the formation of peroxides and other oxygen-containing compounds. The test method for determination of the peroxide number measures those compounds that will oxidize potassium iodide. Thus the magnitude of the peroxide number is an indication of the quantity of oxidizing constituents present. In the test method (ASTM D-1832), a sample is dissolved in carbon tetrachloride and is acidified with acetic acid. A solution of potassium iodide is added, and after a reaction period, the solution is titrated with sodium thiosulfate and a starch indicator. 

The peroxide number of petroleum wax (ASTM D-1832) is determined by dissolving a sample in carbon tetrachloride, acidifying with acetic acid, and adding a solution of potassium iodide any peroxides present will react with the potassium iodide to liberate iodine, which is then titrated with sodium thiosulfate. 

Volumctrically uranium may be determined by reducing an acid solution with zinc or titanous sulfate and oxidizing to the uranyl state by permanganate according to such a reaction as 2 KMnO< + 5 U(SO )2 + 2 H2O = 2 KHSO, + 2 MnSO< + H2SO4 + 5 UO2SO4. A solution of uranyl acetate may be titrated with sodium phosphate. Titration with... 

Iodide is to be titrated coulometrically at constant current at a silver electrode. The sample is 1.0 mM Nal contained in a pH 4 acetic acid solution with 0.1 M sodium acetate having a total volume of 50 mL. 

The amount of the acetic acid released is determined by titration with sodium hydroxide, which makes it possible to determine the amount of hydrogen ions taking part in the hydrolytic reaction. 

Calculate the relative amounts of acetic acid and acetate ion present at the following points when 1 mol of acetic acid is titrated with sodium hydroxide. Also use the Henderson-Hasselhalch equation to calculate the values of the pH at these points. Compare your results with Figure 2.13. 

The acetic-acid content of household vinegar can be determined by potentiometric titration with sodium hydroxide. Mixtures of carbonate and bicarbonate can be analyzed by titration with HCl. 

A method for the determination of amodiaquine hydrochloride in tablets by titration with N-bromosucdnimide has been developed (23). The sample is dissolved in water, treated with an acetic acid solution of the reagent and mixed vnth potassium iodide. The iodine released is titrated with sodium thiosulphate solution. The relative standard deviation for the titration is 2.12% and the recovery is 99.4 -101.0%. 

Acetic and succinic acids were titrated with sodium hydroxyde by using an automatic titration apparatus with potentiometric stop-point indication. Full analyses of partially miscible phases in systems with MIBK and butanol were carried out on a gas chromatograph. 

Benzoic acid and its salts may be determined by titration with sodium hydroxide after extraction of the benzoic acid from an aqueous food suspension into chloroform, and evaporation of the chloroform and any acetic acid present (AOAC method 963.19). Vanillin interferes with this determination and a more selective method involves the determination of benzoic acid in an ether extract by UV absorption at 272 nm, as described in AOAC method 960.38. An alternative method of isolating benzoic acid from food involves the use of steam distillation and TLC separation. These sample preparation techniques are used in AOAC method 967.15 prior to the determination of benzoic acid by UV absorption. 

The esterification equivalent of solid resins is defined as the weight in grams esterified by one mole of monobasic acid. This value includes both the epoxy and hydroxyl groups of the solid resin. It is determined by esterification of the sample with acetic anhydride in the presence of pyridinium chloride, followed by titration with sodium methoxide to a thymol blue-phenolphthalein end point. 

The number of unsaturated bonds can be determined by a titration with a standard solution of bromine dissolved in glacial acetic acid. The sample is also dissolved in glacial acetic acid to which sodium and ammonium acetate are added, so as to give a final concentration of 0-5 and OT M respectively. The cathodic current of bromine is measured with a short circuit system using a rotating platinum indicator, and a calomel or chloranil reference electrode at the potential of the reference electrode. Several unsaturated open chain compounds and terpenes have been titrated in this way.( ) Other modifications of this technique have been used to determine the amount of unsaturation in fats in methanolic solutions. The standard solution of bromine is prepared in methanol, saturated with sodium bromide, and the methylester of stearic acid is added to suppress the maxima. If the methanolic solution is acidified, OT M potassium bromate with OT M sodium bromide can be used instead of bromine. The bromine generated in homogeneous solution can be used to analyse xylenol and cresol fractions of coal-tars. Other phenolic compounds may be similarly determined. The method was used for the determination of small concentrations of styrene... 

Acetic acid, CH3COOH, (M. Wt. 60.05). To prepare approx. IM solution, dilute 57.5 ml of pure glacial acetic acid to 1 litre. Check by titration with alkali against phenolph-thalein. Acetic acid/sodium acetate buffers are prepared by partial neutralization of acetic acid solutions with NaOH NaOAc should not be used. 

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