Alkaline tests

Alkalinity and Lime Content. The whole mud alkalinity test procedure is a titration method which measures the volume of standard acid required to react with the alkaline (basic) materials in an oil mud sample. The alkalinity value is used to calculate the pounds per barrel unreacted excess lime in an oil mud. Excess alkaline materials, such as lime, help to stabilize the emulsion and also neutralize carbon dioxide or hydrogen sulfide acidic gases. 

Weight-up to overcome salt water flow. Chemical treatment as for salt rock. Run alkalinity test and calculate CO3 and HCO3 ions concentration. Calculate lime required ... 

Total alkalinity is generally the most relevant alkalinity test, especially in FT boilers where the FW has a low silica content. Testing for T alkalinity provides the best correlation with pH, corrosion inhibition, and tendencies for carryover. 

The four samples from each location were (1) nonfiltered, nonstabilized water for alkalinity testing, (2) field-filtered, nonstabilized water for nitrate and chloride testing, (3) field-filtered water stabilized with nitric acid for calcium, magnesium, and sodium testing, and (4) field-filtered water stabilized with sulfuric acid for ammonia and phosphate testing. 

Alkalinity Test is one of the std tests for detn of the purity of expls and propellants. It is conducted in the same manner as the acidity test (qv) except that titration is done by 0.05 aq sulfuric acid instead of std aq NaOH sola. (See also under individual explosives and propellants)... 

The acidity or alkalinity is measured as the quantity of cubic centimeters of 0.1 N alkali (NaOH or KOH) or acid solution that are required to neutralize an aqueous extract of 100 g pigment under prescribed conditions. Unless otherwise agreed, the pigment is extracted with hot water. If cold water is used, this must be specifically stated. For standards, see Table 1 ( Acidity/alkalinity ). Test reagents 0.5 N HC1 or H2S04, 0.5 N NaOH or KOH, indicators (by agreement). 

Benzidine.—It is then removed to a basin where it is boiled up slowly with 500 c.cs. water and 120 c.cs. cone, hydrochloric acid and filtered from sine residue. A saturated solution of sodium sulphate is then added until the benzidine sulphate is completely precipitated (test). This is filtered off and is well washed with warm water until free of acid. The moist benzidine sulphate is removed, heated to 50° with a little water, and caustic soda solution (30%) added with stirring until the liquid is just alkaline (test with phenolphthalein). When cold, the free base is filtered off and dried at 50°. It may be crystallised from benzene, alcohol or from hot water (see p. 498). 

Alkalinity Test is one of the std tests for detn of the purity of expls and propellants. It is conducted in the same manner as the... 

Manganese (II) sulfate Brown precipitate of hydrate complex in neutral or alkaline test solution... 

The spot-test technique is as follows. Mix on a spot plate a drop of the alkaline test solution with a drop of a 1 per cent solution of sodium nitroprusside. A violet colour appears. Alternatively, filter paper impregnated with an ammonia-cal (2m) solution of sodium nitroprusside may be employed. 

Place a drop of the alkaline test solution in the distillation apparatus of Fig. 11.59 and evaporate to dryness. Add 5 drops concentrated sulphuric acid and 5 drops pure methanol, stopper the apparatus, and heat to 80°C in a water bath. Collect the methyl borate which distils over in a micro porcelain crucible, waxed on the inside, and containing about 1 ml reagent. A black precipitate forms. For very small amounts of borate it is best to add a few drops of benzidine acetate solution and thus to detect the traces of manganese dioxide by the... 

Place a drop of barium chloride solution upon filter or drop-reaction paper, followed by a drop of a freshly prepared 0-5 per cent aqueous solution of sodium rhodizonate. Treat the reddish-brown spot with a drop of the acid or alkaline test solution. The coloured spot disappears. 

Place a drop of the neutral or alkaline test solution in a micro test-tube, and add 1 drop of m sodium chloride solution and 2 drops of the iron(III) periodate reagent. Carry out a blank test with a drop of distilled water simultaneously. Immerse both tubes for 15-20 seconds in water at 40-50°C. A white (or yellowish-white) precipitate indicates the presence of lithium the blank remains clear. 

Dilute one drop of the alkaline solution with 1 mL of water and add a drop of sodium nitroprusside a purple coloration indicates the presence of sulfur. (2) Prepare a fresh solution of sodium plumbite by adding 10% sodium hydroxide solution to 0.2 mL of 0.1 M lead acetate solution until the precipitate just dissolves, and add 0.5 mL of the alkaline test solution. A black precipitate or a colloidal brown suspension indicates the presence of sulfur. 

Color test for pyrroles. One drop of an aqueous, ethereal, or alkaline test solution is mixed on a spot plate with one or two drops of a 5% solution of p-dimethylamino-benzaldehyde. If pyrrole or a substance capable of forming pyrrole is present, a violet color will appear. The aldehyde condenses with a tautomeric form of pyrrole (3) to give (4), which is converted by hydrogen ion into the colored quinonoid ion... 

The amount of alkalinity in water is typically detennined by Standard Method 2320 (Standard Methods, 1998) and is reported as the equivalent amount of CaCO in milligrams per liter. The purpose of alkalinity testing is to assess the presence of alkaline materials or buffer systems that might interfere with desired chemical reactions, or might promote underside reactions, as discussed in the introductory section of tliis chapter. 

Urea (1) Urease (2) Messier solution On a spot plate treat the neutral or alkaline test solution with reagent (1) and after 2-3 min with reagent (2) Brownish ppt Enzymatic hydrolysis of urea 1... 

The main difference between the alkaline and acidic depolymerization tests is that in the alkaline test a small amount of low polymer is not easily detected because it is soon overshadowed by dissolution of higher polymers. 

The typical results obtained for high alkalinity test waters, with and without ortho-phosphate, are shown in Figure 10.2. Some variation in the lead emissions can often be apparent over the test period, particularly for test waters without ortho-phosphate, and for comparative purposes the data can be... 

Procedure. A drop of the slightly alkaline test solution is evaporated to dryness in a porcelain dish. While the dish is still warm, the residue is stirred with 2 or 3 drops of the reagent. After cooling, the color is observed. In the presence of boric acid, the color changes from blue-violet to greenish-blue. A blank test is necessary only when very small amounts of boric acid are involved. 

Procedure. Three drops of the neutral or alkaline test solution are acidified with a drop of 2 N hydrochloric acid on a spot plate or in a small porcelain... 

The test for iodide by oxidation with nitrite can be carried out [a) on a spot plate or (6) on filter paper containing starch. The spot reaction described under (6) is the more sensitive and is particularly recommended for neutral or alkaline test solutions. 

Procedure I. A drop of 1 50,000 copper sulfate solution is added to the alkaline test solution, followed by a drop of 2 iV alkali hydroxide, and finally a little solid potassium or sodium persulfate. A micro crucible is used. The mixture is boiled. A yellow color indicates periodic acid. 

Procedure. A drop of the neutral or alkaline test solution is mixed in a micro test tube with a drop of a saturated solution of sodium chloride, followed by 2 drops of the reagent. A blauik test with water is started at the same time. Both tubes are dipped in water of 45-50° C for 15-20 seconds. In the presence of lithium, a yellow-white turbidity develops, while the blank remains clear. 

Procedure. A drop of the alkaline test solution and a drop of alkali palladium dimethylglyoxime are brought together on a spot plate a drop of nickel-ammonium solution is then introduced. A red precipitate or pink coloration appears, the shade depending on the amount of alkali cyanide present. A blank test is necessary only when small quantities of cyanide are suspected. 

Sulfites, thiosulfates, and sulfides interfere because they are decomposed by acids the resulting SOg or HgS reduces ferric salts. Black silver sulfide is formed in the case of sulfides. These interferences can be avoided by preliminary oxidation of the neutral or alkaline test solution with several drops of hydrogen peroxide. 

Procedure. A drop of water and a drop of alkaline test solution are placed in adjacent depressions of a spot plate. A drop of 0.2 M sodium sulfide solution is added to each. A drop of methylene blue solution is added to the blank and another to the test solution. Any discharge of the blue color is noted. If the mixture contains considerable quantities of selenium, it loses its color almost at once with smaller amounts the discharge of the blue color is still definitely faster than in the blank test. 

Procedure. A drop of the alkaline test solution is mixed on a spot plate with a drop of 1 % sodium nitroprusside solution. A more or less intense violet appears, depending on the amount of sulfide present. The test may also be carried out on filter paper impregnated with an ammoniacal (5 %) solution of sodium nitroprusside. 

The evaporation residue from a drop of the neutral or weakly alkaline test solution is heated with solid ammonium chloride to 200-300 C. Hydrogen sulfide is evolved and can be detected by means of lead acetate paper Idn. Limit 10 y KCNS. ... 

---