Qualitative testing

The Doctor Test, NF M 07-029 or ASTM D 484, is conducted in qualitative tests for free sulfur, free H2S, and mercaptans. The specifications require a negative Doctor Test for these three types of contaminants. 

Sulfur/butane (qualitative test) NF M 41-006 Sodium plumbite test (interface coloration)... 

Vapours which can be readily condensed e.g., chloroform, aniline, nitro-benzene, etc.) are readily detected by the device shown in Fig. 5 i(b). It is essentially a cold finger with a deep indentation or weU at the lower end. In this way two or three drops of liquid can easily be collected and removed by a capillary tube for qualitative tests. 

Derivatives. The precise identification of a compound normally depends upon the preparation of a derivative and the determination of physical constants such as m.p. in the case of a solid. Many simple compounds can, however, be identified with a fair degree of certainty by intelligently-selected qualitative tests alone, e.g., formates, oxalates, succinates, lactates, tartrates, chloral hydrate. 

Qualitative tests and chemical degiadation have been to a large degree replaced by mstiumental methods of stiuctuie deteimmation The most prominent methods and the stiuctuial clues they provide are... 

These equations tell us that the reverse process proton transfer from acids to bicarbon ate to form carbon dioxide will be favorable when of the acid exceeds 4 3 X 10 (pK, < 6 4) Among compounds containing carbon hydrogen and oxygen only car boxylic acids are acidic enough to meet this requirement They dissolve m aqueous sodium bicarbonate with the evolution of carbon dioxide This behavior is the basis of a qualitative test for carboxylic acids... 

Oxidation with Benedict s reagent (Section 25 19) Sugars that con tain a free hemiacetal function are called reducing sugars They react with copper(ll) sulfate in a sodium citrate/sodium carbonate buffer (Benedict s reagent) to form a red precipitate of copper(l) oxide Used as a qualitative test for reducing sugars... 

Alnminon (qualitative test for aluminum). The reagent consists of 0.1% solution of the ammonium salt of aurin tricarboxylic acid. A bright red precipitate, persisting in alkaline solution, indicates aluminum. 

Phenyhsonitrile has a powerful characteristic odor it is used as a qualitative test (the carbylamine test) for chloroform or primary aromatic amines. Chloroform reacts with phenols in alkaline solution to give hydroxyaromatic aldehydes in the Reimer-Tiemann reaction eg, phenol gives chiefly Nhydroxyben2aldehyde and some sahcylaldehyde (11) (see Hydroxybenzaldehydes). 

The absorption spectrum of this nonstoichiometric phase forms the basis for the formerly much-used qualitative test for zinc oxide yellow when hot, white when cold . Alternatively, anion sites can be left vacant, e.g. ... 

With the exception of the fluorides, the halides are all very water-soluble and deliquescent, Precipitation of the insoluble fluorides can be used as a qualitative test for these elements. The distinctive ability of Sc to form complexes is illustrated by the fact that an excess of F causes the first-precipitated SCF3 to redissolve as... 

HgCl2 + Hg) the HgCl2 then reacts as outlined above to give a precipitate of variable composition. The liberated mercury, however, renders the precipitate black, as previously mentioned, and so forms the basis of a distinctive qualitative test for Hg2. ... 

Compounds containing a reasonable proportion of an enolie hydroxyl group, i.e., C=C—OH, usually give a deep color with ferric chloride, and this has often been used as a qualitative test. In this way, 2-hydroxythiophene has been shown to exist, at least in part, in the hydroxy form, ... 

The first commercially successful pneumatic tire was developed in 1888 in Belfast by the Scottish veterinarian John Boyd Dunlop primarily to improve the riding comfort of bicycles. Dunlop also showed, albeit qualitatively, that his air-inflated pneumatic took less effort to rotate than did the solid rubber tires in use at that time. His qualitative tests were the first known rolling resistance experiments on pneumatic tires. Due to this significant reduction in rolling loss, many professional cyclists in Britain and Ireland adopted air-inflated tires for their bicycles by the early 1890s. Pneumatics for the nascent automobile industry soon followed. 

There is not much data available on this point. Operational experience plus qualitative tests indicate that entrainment is negligible until the packing reaches the flooding condition. See discussion under distillation section. 

Oxidizing agents also attack the double bond. When a reaction between an unsaturated compound and the permanganate ion occurs, the violet color of permanganate fades. This reaction, as well as reaction (29b) in which a color change also occurs, is used as a qualitative test for the presence of double bonds in compounds. 

Most precipitates are produced in the presence of one or more soluble compounds. Since the latter are frequently not volatile at the temperature at which the precipitate is ultimately dried, it is necessary to wash the precipitate to remove such material as completely as possible. The minimum volume of the washing liquid required to remove the objectionable matter should be used, since no precipitate is absolutely insoluble. Qualitative tests for the removal of the impurities should be made on small volumes of the filtered washing solution. Furthermore, it is better to wash with a number of small portions of the washing liquid, which are well drained between each washing, than with one or two large portions, or by adding fresh portions of the washing liquid while solution still remains on the filter (see Section 11.8). 

In all cases, tests for the completeness of washing must be made by collecting a small sample of the washing solution after it is estimated that most of the impurities have been removed, and applying an appropriate qualitative test. Where filtration is carried out under suction, a small test-tube is placed under the crucible adapter. 

Qualitative Test of Dynamic Strength of Various Plastic-Bonded And Fiber-Reinforced Explosives , BRL, APG, MR 977 (1956) 16) K.G. 

Moisture—when purchased dry - max 0.20 percent when purchased wet - max 22.0 percent Ash - Max 0.1 percent Insoluble matter — Max 0.1 percent Acidity - total sulfuric acid - max 0.1 percent nitric acid - none Lead - max 0.004 percent Analytical A qualitative test for PA depends on its reaction with aq KCN to form a red colored salt, the so-called isopurpuric acid . The reactions involved in this test are still in doubt (see Ref 35, p 492). PA is one of the few tri-nitroaromatics that does not produce a reddish coloration with strong alkalis (Ref 46). It has... 

For the qualitative test one has to carry out dediazoniations with a diazonium ion labeled with 15N in either the a- or P-position or both, in a solution containing the highest possible concentration of unlabeled molecular nitrogen (14N2). If the reaction is stopped before completion, the 15N content of the residual diazonium ion should be smaller due to the reverse reaction of (a) in Scheme 8-8. The result of this test was indeed positive (Bergstrom et al., 1974, 1976). 

The unit starts with a survey of the surroundings in which students familiarise themselves with the names, physical properties and uses of common metals. The use of symbols to represent metals is also introduced. Discussion of the physical properties which metals have in common then leads to the idea that different metals can be identified by their chemical properties. Students complete simple qualitative tests on known metals and use these tests to identify metals in common objects. 

UicAochAornatogAoptiic TcAtcng MetkodA ioA Sickle, Cell Anemia and Related Vl60AdeAA in the AdixJit. The procedures described in the preceding Section are, in fact, applicable to the detection of hemoglobinopathies in the adult, and any quantitative determination of Hb-A2 immediately becomes a qualitative test for abnormal Hb s. If, instead of the very small zone of Hb-A2, a prominent zone moves in the same way, Hb-C (or Hb- ) is indicated. 

Table 9.1. Specific (1+ and / ) and average (Iav) information contents (in bit) and specific plausibilities (77+ and il ) in cases of various a priori probabilities of qualitative tests... 

Fig. 9.1. Signal states in the case of qualitative tests ( + means signal detected (z+) and cc—cc means not detected (z )...

In contrast to quantitative analyses, the results of qualitative tests and of identifications cannot be evaluated by means of mathematical statistics. Instead, information theory is a helpful tool to characterize qualitative analyses, in particular in case of multicomponent systems. 

In contrast to qualitative tests, in quantitative analysis more than the two signal states shown in Fig. 9.1 (+/—) are evaluated. Depending on the un-... 

In the concrete case of qualitative tests on n components, the maximum information amount is M(n)quai = n bit. 

A qualitative test of some value is to fire the explosive standing on its end on a plate of lead about 2 -5 cm thick. A strong high velocity explosive... 

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