Soda lime, ignition with

An additional useful test is to distil the acid or its sodium salt with soda lime. Heat 0.5 g. of the acid or its sodium salt with 0 2 g. of soda lime in an ignition tube to make certain that there is no explosion. Then grind together 0-5 g. of the acid with 3 g. of soda hme, place the mixture in a Pyrex test-tube and cover it with an equal bulk of soda hme. Fit a wide dehvery tube dipping into an empty test-tube. Clamp the tube near the mouth. Heat the soda lime first and then the mixture gradually to a dull-red heat. Examine the product this may consist of aromatic hydrocarbons or derivatives, e.g., phenol from sahcyUc acid, anisole from anisic acid, toluene from toluic acid, etc. 

Interaction is exothermic, and if air is present, incandescence may occur with freshly prepared granular material. Admixture with oxygen causes a violent explosion [1], Soda-lime, used to absorb hydrogen sulfide, will subsequently react with atmospheric oxygen and especially carbon dioxide (from the solid coolant) with a sufficient exotherm in contact with moist paper wipes (in a laboratory waste bin) to cause ignition [2], Spent material should be saturated with water before separate disposal. Mixture analogous to soda-lime, such as barium hydroxide with potassium or sodium hydroxides, also behave similarly [1],... 

Sulphur. — Thoroughly mix 5 gm. of finely powdered soda-lime with 2 gm. of sodium nitrate, and ignite the mixture in a silver crucible. Dissolve the melt in 50 cc. of water with 20 cc. of hydrochloric acid, filter, and to the filtrate add barium chloride solution. No precipitate of barium sulphate should form within twelve hours. 

There are three straightforward tests which will provide useful information as to the general properties of the compound, and the presence of the more important of the elements noted above other than carbon, hydrogen and oxygen these tests are the ignition test heating with soda-lime and the sodium fusion test (Lassaigne s test). 

Soda lime When salicylic acid or one of its salts is heated with excess of soda lime in an ignition tube, phenol, C6Hs(OH), is evolved, which may be recognized by its characteristic odour. 

Soda lime Benzoic acid and benzoates, when heated in an ignition tube with excess soda lime, are decomposed into benzene, C6H6, which bums with a smoky flame, and carbon dioxide, the latter combining with the alkali present. 

Ignites on contact with metal oxides (e.g., barium peroxide, chromium trioxide, copper oxide, lead dioxide, manganese dioxide, nickel oxide, silver(I) oxide, silver(II) oxide, sodium peroxide, thallium(III) oxide, mercury oxide, calcium oxide, nickel oxide), oxidants (e.g., silver bromate, heptasilver nitrate octaoxide, dibismuth dichromium nonaoxide, mercury(I) bromate, lead(II) hypochlorite, copper chromate, fluorine, nitric acid, sodium peroxide, lead(IV) oxide), rust, soda-lime + air. Reacts violently with NI3, NF3, p-bromobenzenediazonium chloride, OF2, F2, Cu, CIO, BrFs,... 

E) Detection of Nitrogen. (1) Calcium Oxide Fusion. Mix 0.1 g of urea or casein with five times its bulk of pulverized soda lime. Place in a small evaporating dish, and cover with a watch glass, on the inner surface of which is laid a strip of moist red litmus paper. Now heat gently to avoid spattering, and observe the litmus paper. Allow the ignition mixture to cool, place a portion In a test tube, and test for sulfide ion. 

B) Preparation of Benzene. Prepare benzene by heating a mixture of 5 g of sodium benzoate with 4 g of soda lime in an ignition tube fitted with a cork and with a delivery tube leading into a test tube immersed in cold water. Note the characteristic odor of the distillate. Devise a test for proving the presence of benzene. Consult the instructor and perform the test. 

The plumbite treated fabric cut to desired shape is heated in a closed oven to approximately 600 0 with the fabric in surface contact with either a silicate glass or porcelain It is important that the oven remain closed while the temperature is raised to about 300 C to prevent ignition of the fabric Above 300 C the oven can be opened periodically for examination of the sample The temperature of 600 C is maintained for about 1 h The maximum temperature required will vary soiaewhat depending on the siliceous substrate used Temperatures as low as 550 C with soda-lime glass and as high as 700 C with borosilicate glasses have been used with success ... 

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