Barium tests

The sulphate ion is detected by addition of barium chloride in the presence of hydrochloric acid a white precipitate of barium sulphate is obtained. The same test can be used to estimate sulphate, the barium sulphate being filtered off, dried and weighed. 

Oxidation of a sulphur compound with concentrated nitric acid yields sulphuric acid or a sulphate, which can be tested for with barium chloride. This can be used to estimate the sulphur. 

In similar circumstances, silver salts leave a residue of metallic silver lead and copper salts usually leave a residue of the corresponding oxide calcium and barium salts leave a resirlne of the carbonate or oxide. Identify the metal in all such cases by the usual tests of qualitative inorganic analysis. Metals other than the above are seldom encountered in elementan qualitative analysis. 

Extract the acidified solution with ether, remove the ether and identify the phenol in the usual manner (see Section IV,114).f Add a few drops of bromine water or nitric acid to the aqueous layer and test for sulphate with barium chloride solution. 

Two grams of the oU are saponified the portion insoluble in water separated by shaking with ether, and the aqueous solution neutralised with acetic acid. The solution is dUuted to 50 c.c. and 10 c.c. of cold saturated solution of barium chloride added. It is then warmed for two hours on a water-bath and allowed to cool. If a crystalline deposit is formed, the oil is to be considered adulterated, as the acids contained in normal lavender oil, acetic and butyric acids, give soluble barium salts. It is evident that this test will only detect those acids whose barium salts are insoluble. A more comprehensive test is therefore needed, as several other esters have since been employed for adulteration purposes. Glycerin acetate, prepared by the acetylation of glycerine, was first de-... 

The Deamination of Adenosine 20 g of adenosine are dissolved in one liter of water by warming, and after cooling to room temperature 120 g of barium nitrite (monohydrate) are added to the solution. Under stirring there is added in time intervals of one hour 160 cc of 2N sulfuric acid after each time interval. After the third addition, the reaction mass is allowed to stand for 3 hours at room temperature. The solution is then tested for barium, and if some barium is still present a slight excess of sulfuric acid is added. 300 cc of methanol is then added. In order to drive off the excess of nitrous acid, CO is conducted... 

Procedure. Weigh out accurately about 0.3 g of the solid (ora sufficient amount to contain 0.05-0.06 g of sulphur) into a 400 mL beaker, provided with a stirring rod and clockglass cover. Dissolve the solidf in about 25 mL of water, add 0.3-0.6 mL of concentrated hydrochloric acid, and dilute to 200-255 mL. Heat the solution to boiling, add dropwise from a burette or pipette 10-12 mL of warm 5 per cent barium chloride solution (5 g BaCl2,2H20 in 100 mL of water — ca 0.2M). Stir the solution constantly during the addition. Allow the precipitate to settle for a minute or two. Then test the supernatant liquid for... 

Barium. Pptd by the addn of Ba chloride to w-sol salts of MEDNA (Ref 2 3) it has the least expl effect in lead plate test when primed with MF (Ref 7)... 

Self-Test H.1A When aluminum is melted and heated with solid barium oxide, a vigorous reaction takes place, and elemental molten barium and solid aluminum oxide are formed. Write the balanced chemical equation for the reaction. 

Sei f-Test 14.6B Write the chemical equation for the reaction of barium with oxygen. 

Students usually identify the existence of anions such as carbonate, iodide and sul-fate(VI) by adding a barium/silver(I)/lead(II) solution to the unknown, followed by a dilute acid or vice-versa in qualitative analysis practical work sessions and examinations. Mat r students had difficulty understanding the roles of the bar-ium/silver(I)/lead(II) solution and the dilute acid in the tests for anions. For example, 20% believed that the addition of aqueous barium nitrate(V) followed by dilute nitric(V) acid was to test for sulfate(VI) only. Another 25% believed that to test for a carbonate, acid had to be added directly to the unknown sample, while 20% believed that the addition of barium nitrate(V) invalidated the test for carbonates. When the students were asked the purpose of adding dilute nitric(V) acid following die addition of silver nitrate(V) solution (in one question) and lead(II) nitrate(V in another question) to the unknown solutions, 22% and 35%, respectively, indicated... 

In the particular example shown, zinc sulfate and barium hydroxide are being dispensed into the test tube so as to precipitate the proteins. The filtrate obtained is the filtrate from 10 microliters of serum. This can be used for several purposes and in the application being referred to, an amount equivalent to 3 microliters is being used for sugar determination, by the hexokinase procedure and an amount equivalent to 3 microliters is being used for urea estimation with diacetylmonoxime (15). 

Barium peroxide had been used instead of potassium permanganate to purify acetic anhydride. Several operations had been carried out and the technicians had realised that this medium gives rise to mild deflagrations. During the last test a very violent detonation took place. It was thought that acetyl peroxide had formed. 

Figura 2.9 Dse of th Grob test Mixture to compare tbe activity of various glass surfaces coated with ov-ioi. Surface types A > Untreated pyrex glass, B pyrex glass deactivated by thermal degradation of Ceurbowax 20M, C < SCOT column, prepared with Silanox 101, D pyrex glass column coated with a layer of barium carbonate and deactivated as in (B), and E - untreated fused silica. Components are identified in Table 2.7 with ac - 2-ethylhexanoic acid. (Reproduced with permission from ref. 152. Copyright Elsevier Scientific Publishing Co.)...

Pour 3 mL of 0.2M barium chloride into a clean test tube. Slowly add 3 mL of 0.2M sodium sulfate. 

Radiologic and/or endoscopic procedures are usually required to objectively document the presence of ulcers. Barium studies have a high sensitivity and are considered first-line tests to radiographically document an ulcer. However, the cost and complexity of all of these tests has led to the promotion of an early empiric treatment strategy for patients at low risk for PUD-related sequelae (e.g., malignancy). An empiric treatment strategy is appropriate for patients less than 50 years of age who have mild or intermittent epigastric symptoms and no evidence of PUD-related systemic symptoms or complications. 

ALFT Abnormal liver function test BE Barium enema... 

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