Hydrochloric acid activity determination with

Extract the activated carbon from the reactor after it cools. Wash the carbon with a 15% hydrochloric acid solution. Determine the presence of iron qualitatively in the wash water. 

The solubility in a 1 x 10 to 1 x 10 M solution of sulphuric, nitric, or hydrochloric acid was determined after equilibration for 8 hours with continuous stirring. Two acids were used for each selenite with two or three experiments performed with each acid. The solid and solution were separated by centrifugation and the metal ion concentration in the saturated solution was determined. The total selenite concentration was calculated from the total metal ion concentration. The pH values of the start and equilibrium solutions were measured with a glass electrode calibrated against the quin-hydrone electrode. The pH scale is somewhat undefined but can probably be regarded as an activity scale. 

Analysis for active oxygen is necessary (treatment with hydrochloric acid and determination by the Bunsen method). 

For quantitative evaluation, sample- and standard solution are chromatographed on the same layer, the zones of active substance locahsed in UV fight or after spraying a reference strip, scraped off and extracted with 0.2 N sulphuric acid [130] or 0.05 N hydrochloric acid. The determination is then carried out by photometry, polarography, spectrophotometry [130, 143] or spectrofluorometry. 

Reamer et al have discussed the applicability of a gas chromatograph coupled with a microwave plasma detector (GC-MPD) for the determination of tetraalkyllead species in the atmosphere. The tetra-alkyllead species are collected by a cold trap. The volatile lead species are concentrated within an organic solvent, separated by a gas chromatographic column and determined by an MPD system which measures the emission intensity of the lead 405.78 nm spectral line. Previous workers have used an acidic solution of hydrochloric acid > activated charcoal , Apiezon L on a silanized universal sup-port the chromatographic support OV-1 and silicone rubber on Chromosorb to collect alkyllead compounds from the atmosphere. 

Analyses of alloys or ores for hafnium by plasma emission atomic absorption spectroscopy, optical emission spectroscopy (qv), mass spectrometry (qv), x-ray spectroscopy (see X-ray technology), and neutron activation are possible without prior separation of hafnium (19). Alternatively, the combined hafnium and zirconium content can be separated from the sample by fusing the sample with sodium hydroxide, separating silica if present, and precipitating with mandelic acid from a dilute hydrochloric acid solution (20). The precipitate is ignited to oxide which is analy2ed by x-ray or emission spectroscopy to determine the relative proportion of each oxide. 

Thomas and Long488 also measured the rate coefficients for detritiation of [l-3H]-cycl[3,2,2]azine in acetic acid and in water and since the rates relative to detritiation of azulene were similar in each case, a Bronsted correlation must similarly hold. The activation energy for the reaction with hydronium ion (dilute aqueous hydrochloric acid, = 0.1) was determined as 16.5 with AS = —11.3 (from second-order rate coefficients (102At2) of 0.66, 1.81, 4.80, and 11.8 at 5.02, 14.98, 24.97, and 34.76 °C, respectively). This is very close to the values of 16.0 and —10.1 obtained for detritiation of azulene under the same condition499 (below) and suggests the same reaction mechanism, general acid catalysis, for each. 

An example of a chemical reaction with a measurable energy change is the reaction of an acid and a base. In this activity, you will determine whether the reaction of hydrochloric acid (HCI) with sodium hydroxide (NaOH) absorbs or liberates heat. 

After adjusting to 2 mol 1 1 in hydrochloric acid, 500 ml of the sample is adsorbed on a column of Dowex 1-XS resin (Cl form) and elution is then effected with 2 M nitric acid. The solution is evaporated to dryness after adding 1M hydrochloric acid, and the tin is again adsorbed on the same column. Tin is eluted with 2 M nitric acid, and determined in the eluate by the spectrophotometric catechol violet method. There is no interference from 0.1 mg of aluminium, manganese, nickel, copper, zinc, arsenic, cadmium, bismuth, or uranium any titanium, zirconium, or antimony are removed by ion exchange. Filtration of the sample through a Millipore filter does not affect the results, which are in agreement with those obtained by neutron activation analysis. 

A 10 g sample is roasted at 650°C and decomposed with hydrochloric acid/hydrogen peroxide. The Pt and Pd in the solution is pre-concentrated using adsorbent materials which are composed of active charcoal and anion resin. The adsorbent materials are washed sequentially with 2% ammonium bifluoride, 5% hydrochloric acid and distilled water, and subsequently ashed in a muffle furnace at 650°C. The total residue of ca. 0.25 mg is dissolved with 2 ml fresh aqua regia, then diluted to 5ml using 10% hydrochloric solution, and determined using ICP-MS, which has a detection limit of 0.2 ppb for Pt and Pd. The residue can also be mixed with a spectral buffer, and determined by DC-arc ES, which has detection limits of 0.3 ppb for Pt and 0.2 ppb for Pd. 

The contents of the nucleic acid bases in the poly-L-lysine derivatives were determined by UV spectra of the polymers after hydrolysis The polymers were hydrolyzed in 6 N-hydrochloric acid at 105°C for 24 hr, into lysine dihydrochloride and the carboxyethyl derivatives of the nucleic acid bases. The quantitative calculation was made relative to the standard sample of the carboxyethyl derivative of the nucleic acid bases. The analytical data are listed in Table 1. It was found that the thymine and uracil derivatives was completely substituted to polylysine. Low value in case of adenine base in the polymer may be attributed to the unstability of the activated ester, Ade-PNP (2), and may also be explained in terms of the steric interaction among bulky pendant groups of the polymer. When the poly-L-lysine containing about 50 mol % adenine units was again treated with Ade-PNP, the adenine unit content in the polymer increased up to 74 mol %(,] ). 

The direct potentiometric determination (using a cation-selective membrane electrode) of procaine and some physiologically active amines in pharmaceuticals has been reported [70]. The sensing membrane was formed from PVC plasticized with dibutyl phthalate, and contained 0.1 mM trioctyloxybenzene-sulfonic acid in dibutyl phthalate. The reference solution was a mixture of 1 mM solution of the organic base and hydrochloric acid. Response was found to be linear over a wide concentration range, and the method was highly selective. 

The homogenization of liver, kidney, and muscle tissues with glycine-hydrochloric acid buffer was presented for the determination of OTC, TC, and CTC. The supernatant was purified on a cyclohexyl SPE cartridge previously activated with MeOH and water. The TCs were eluted with MeOH, which was evaporated at 65°C, and the residue was dissolved in mobile phase. Recoveries were achieved greater than 70% in muscle at the MRL concentrations and higher than 60% for kidney with RSD <11%. Gradient elution was employed to improve the separation of OTC and TC from interference found in kidney samples. The eluate from HPLC was mixed with aluminium chloride solution in a low-volume T-piece and delivered into the PTFE tubing 13.7 m X 0.3 mm immersed in an oil bath at 60°C followed by fluorescent detection (22). 

For chemical analysis, we used a mild acid-extraction procedure, based on recent experimental work (13, 26, 36, 37). We chose the extraction procedure over total digestion of the sample (35) because we are interested specifically in anthropogenic inputs by way of inorganic P and other elements, and not the total compositional chemistry (i.e., anthropogenic and diagenetic inputs). The extractant we used, composed of 20 ml of dilute 0.60 molar hydrochloric acid and 0.16 molar nitric acid, has been experimentally determined to remove soluble and readily labile P and other elements. While the extraction is not always proportional to the total P (or other elements) in soil, for activity area research we are concerned with the spatial patterns of elemental concentrations rather than absolute concentrations, as many variables affect elemental levels in soils (39, 40). 

The content of acid-soluble iron in paper is determined by TAPPI standard T434 (iron combined in clay and other complex compounds is presumed to be nonreactive). The presence of iron can be shown by the color produced upon wetting the paper briefly with warm 6N hydrochloric acid and then adding a solution of potassium ferrocyanide or thiocyanate localized specks of iron or rust are indicated by the more intense color formation. Complete analysis of paper for metallic elements has been accomplished by chemical procedures, emission spec-trography, scanning electron microscopy/x-ray, and neutron activation. 

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