Standard potassium nitrate

The physical properties of the hollow fibers were evaluated after each activation step,following the diffusion coefficient of standard potassium nitrate and riboflavin. As shown in table 2,the activation did not adversely change the peculiarity of semipermeable membrane. 

Addition of silver nitrate to a solution of a chloride in dilute nitric acid gives a white precipitate of silver chloride, AgCl, soluble in ammonia solution. This test may be used for gravimetric or volumetric estimation of chloride the silver chloride can be filtered off, dried and weighed, or the chloride titrated with standard silver nitrate using potassium chromate(VI) or fluorescein as indicator. 

Pipette 25 mL of an aluminium ion solution (approximately 0.01 M) into a conical flask and from a burette add a slight excess of 0.01 M EDTA solution adjust the pH to between 7 and 8 by the addition of ammonia solution (test drops on phenol red paper or use a pH meter). Boil the solution for a few minutes to ensure complete complexation of the aluminium cool to room temperature and adjust the pH to 7-8. Add 50 mg of solochrome black/potassium nitrate mixture [see Section 10.50(C)] and titrate rapidly with standard 0.01 M zinc sulphate solution until the colour changes from blue to wine red. 

Pipette 25 mL of the bismuth solution (approx. 0.01 M) into a 500 mL conical flask and dilute with de-ionised water to about 150 mL. If necessary, adjust the pH to about 1 by the cautious addition of dilute aqueous ammonia or of dilute nitric acid use a pH meter. Add 30 mg of the xylenol orange/potassium nitrate mixture (see Section 10.50) and then titrate with standard 0.01 M EDTA solution until the red colour starts to fade. From this point add the titrant slowly until the end point is reached and the indicator changes to yellow. 

Procedure. Pipette 25 mL of the test solution (which may contain both calcium and lead at concentrations of up to 0.01 M) into a 250 mL conical flask and dilute to 100 mL with de-ionised water. Add about 50 mg of methylthymol blue/potassium nitrate mixture followed by dilute nitric acid until the solution is yellow, and then add powdered hexamine until the solution has an intense blue colour (pH ca 6). Titrate with standard (0.01 M) EDTA solution until the colour turns to yellow this gives the titration value for lead. 

Pipette 25 mL of the solution containing magnesium, manganese and zinc ions (each approx. 0.02M), into a 250 mL conical flask and dilute to 100 mL with de-ionised water. Add 0.25 g hydroxylammonium chloride [this is to prevent oxidation of Mn(II) ions], followed by 10 mL of the buffer solution and 30-40 mg of the indicator/potassium nitrate mixture. Warm to 40 °C and titrate (preferably stirring magnetically) with the standard EDTA solution to a pure blue colour. 

The following sections are concerned with the use of standard solutions of reagents such as silver nitrate, sodium chloride, potassium (or ammonium) thiocyanate, and potassium cyanide. Some of the determinations which will be considered strictly involve complex formation rather than precipitation reactions, but it is convenient to group them here as reactions involving the use of standard silver nitrate solutions. Before commencing the experimental work, the theoretical Sections 10.74 and 10.75 should be studied. 

The indicator electrode must be reversible to one or the other of the ions which is being precipitated. Thus in the titration of a potassium iodide solution with standard silver nitrate solution, the electrode must be either a silver electrode or a platinum electrode in the presence of a little iodine (best introduced by adding a little of a freshly prepared alcoholic solution of iodine), i.e. an iodine electrode (reversible to I-). The exercise recommended is the standardisation of silver nitrate solution with pure sodium chloride. 

Absorbance scale. This can be checked by using one or more standard solutions which have been carefully prepared examples include potassium dichromate in either acid or alkaline solution, and potassium nitrate solution. Full details of recommended standard solutions and of their standard absorption values are given in Ref. 19. 

A weighed amount of sample is dissolved in a mixture of propanone and ethanoic acid and titrated potentiometrically with standard lead nitrate solution, using glass and platinum electrodes in combination with a ferro-ferricyanide redox indicator system consisting of 1 mg lead ferrocyanide and 0.5 ml 10% potassium ferricyanide solution. The endpoint of the titration is located by graphical extrapolation of two branches of the titration plot. A standard solution of sodium sulfate is titrated in the same way and the sodium sulfate content is calculated from the amounts of titrant used for sample and standard. (d) Water. Two methods are currently available for the determination of water. 

Chlorine at the percentage level at which it occurs in sea water is usually determined by classical procedures using standard silver nitrate as the titrant and potassium chromate indicator, or alternatively by the mercuric thiocyanate procedure using dithizone as indicator. As large dilutions of the original sample are involved in these analyses, it is essential to use grade A glassware and take all other suitable precautions, such as temperature control. 

The following substance, namely magnesium acetate potassium citrate potassium hydroxide potassium nitrate and sodium chloride can also be assayed for their respective elements as shown in Table 25.1 below. However, all the respective solutions of the said pharmaceutical substance and their standard solutions must be prepared as prescribed in BP (1993) strictly to obtain the best results. 

CBL System voltage probe filter paper (6 pieces size 0.6 cm by 2.5 cm) 1M potassium nitrate forceps steel wool or sandpaper table of standard reduction potentials... 

Equipment needed for the above procedures is not always available in the standard laboratory. A useful and widely used method for preparing solutions of dinitrogen pentoxide in nitric acid involves the distillation of mixtures of oleum and potassium nitrate in absolute nitric acid. Another method uses a solution of sulfur trioxide and ammonium nitrate in nitric acid. Although the original report states that solutions of 28 2 % dinitrogen pentoxide in nitric acid can be prepared via this method, a later report suggests that concentrations higher than 30 % are not attainable. 

Nitrate stock standard solution, 0.2 mg mh nitrate-N - dissolve 0.722 g of potassium nitrate in 0.01 M CaSO solution, dilute to 500 ml and store in a refrigerator. 

Nitrate-N standard solution, 0.14 mg mh nitrate-N - dissolve 1.011 g potassium nitrate (oven-dry) in water, transfer with washings to a 1-1 volumetric flask, make up to the mark and mix. 

THE properties and purity standards of ammonium nitrate — a chief ingredient of these mixtures—have been discussed earlier (p. 463, Vol. II), and so has the purity of potassium nitrate (p. 343). The other ingredients should meet the requirements of high purity demanded in the commercial products. 

In practice it is convenient to standardize the nitrometer from time to time by means of a sample of pure potassium nitrate (13.85% N) or of nitrocellulose of known nitrogen content. 

The chlorides may also be determined vohrmetrically by the following method,1 which effects the removal of the phosphates from the beer 50 c.c. of the beer are evaporated with 0-5 gram of barium carbonate and subsequently ignited to a black ash. The latter is extracted with hot water and filtered, the filtrate being then titrated with standard silver nitrate solution in presence of potassium chromate as indicator. 

Often, greater accuracy may be obtained, as in Volhard type titration, by performing a back titration of the excess silver ions. In such a case, a measured amount of standard silver nitrate solution is added in excess to a measured amount of sample. The excess Ag+ that remains after it reacts with the analyte is then measured by back titration with standard potassium thiocyanate (KSCN). If the silver salt of the analyte ion is more soluble than silver thiocyanate (AgSCN), the former should be filtered off from the solution. Otherwise, a low value error can occur due to overconsumption of thiocyanate ion. Thus, for the determination of ions (such as cyanide, carbonate, chromate, chloride, oxalate, phosphate, and sulfide, the silver salts of which are all more soluble than AgSCN), remove the silver salts before the back titration of excess Ag.+ On the other hand, such removal of silver salt is not necesary in the Volhard titration for ions such as bromide, iodide, cyanate, thiocyanate, and arsenate, because the silver salts of these ions are less soluble than AgSCN, and will not cause ary error. In the determination of chloride by Volhard titration, the solution should be made strongly acidic to prevent interference from carbonate, oxalate, and arsenate, while for bromide and iodide analysis titration is carried out in neutral media. 

For the determination of nitrate, use a 1 dram vial with a polyethylene stopper (Kimble No. 60975-L) as a reaction vessel. Introduce a 0.20ml aliquot of aqueous sample into the vial, followed by 1.0ml of thiophen free benzene. Catalyse the reaction by addition of 1.0ml of concentrated sulphuric acid. Shake the vial for lOmin. Remove the benzene layer immediately from the reaction vial with a Pasteur pipette, place it in a separate vial and analyse by gas chromatography with electron capture detection for the nitrobenzene concentration generated. Treat standard solutions of potassium nitrate in the same manner to generate a standard calibration plot relating nitrobenzene concentration to peak height. If higher precision is desired (approximately 4% relative standard deviation), add 2,5-dimethylnitrobenzene to the benzene prior to reaction. 

For compounds containing chlorine or bromine, a weighed sample is dissolved in 10 ml. of methanol 10 ml. of 20% sodium hydroxide, 2 g. of zinc, and 0.5 g. of Raney nickel are added, and the mixture is heated with reflux for 1 hour over a water bath. It is then cooled and decanted. After acidification with nitric acid, 20 ml. of standard silver nitrate solution and 5 ml. of a ferric alum solution are added, and the solution is titrated with standard potassium thiocyanate. The procedure is modi-... 

The standard composition is 75% potassium nitrate, 10% sulfur and 15% charcoal. There are also graded compositions containing 74, 70, 68 or 64 % potassium nitrate. Corresponding compositions based on sodium nitrate are known as -> B-Black Powder. 

Standard substances are potassium chlorate 1 (adapted by JIS as an extra pure reagent) and potassium nitrate 2 (adapted by JIS as a guaranteed reagent), and the particle size of each must be such that it passes through a standard 300 /jl m sieve (about 50 mesh) and does not pass through a 150 fJ. m sieve (about 100 mesh). Standard substances should be held more than 24 hours in a desiccator with silica gel for drying. 

Standard Nitrate Solution Transfer 8.022 g of potassium nitrate (KN03), previously dried at 105° for 1 h, into a 500-mL volumetric flask, dissolve in and dilute to volume with water, and mix well. Slowly add 5.0 mL of this solution from a buret into 400 mL of ACS Reagent-Grade Sulfuric Acid, previously cooled to 5°, keeping the tip of the buret below the surface of the acid. After the solution has reached room temperature, transfer it into a 500-mL volumetric flask, and dilute to volume with ACS Reagent-Grade Sulfuric Acid. Each milliliter contains 100 (xg of nitric acid (HN03). 

Many catalysts used in chemical synthesis can be treated in the same way, often the nitrous oxide/acetylene flame is used because of the refractory nature of the elements to be determined. Harrington and Bramstedt [56] have determined rhenium in electro-chemical surface catalysts by stripping the coating with molten potassium hydroxide/ potassium nitrate. This melt was extracted with hydrochloric acid, the residue was fused with sodium peroxide for further rhenium determination. Titanium, being the substrate on which the catalyst was coated, was added to the standards, an air/acetylene flame and 343.3 nm were used for the finish. 

The standards shown have been the most commonly utilized although others such as nitric acid, formamide, and potassium nitrate have also been reported. 

Standards for calibration of absorbance and wavelength are necessary. Certified nichrome metal fihn filters can be used in the ultraviolet range but usually a solution of pure potassium dichromate is used, for which accepted specific absorbance values are known (Table 2). Other standards which have been proposed for the ultraviolet range are potassium nitrate in water and potassium chromate in dilute potassium hydroxide solution for the visible range, coppersulphate and ammonium sulphate havebeen used. 

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