Sodium hydrogen carbonate 0.1 molar

CHEMICAL NAME = sodium hydrogen carbonate CAS NUMBER = 144-55-8 MOLECULAR FORMULA = NaHC03 MOLAR MASS = 84.0 g/mol... 

Predict the pH region in which each of the following buffers will be effective, assuming equal molarities of the acid and its conjugate base (a) sodium nitrite and nitrous acid (b) sodium formate and formic acid (c) sodium carbonate and sodium hydrogen carbonate (d) ammonia and ammonium chloride ... 

When tellurium tetrachloride and acetone (1 2 molar ratio) are refluxed in dry chloroform, 2-methyl-4-oxo-2-penten-l-yl tellurium trichloride is formed in 43% yield. This compound can be obtained in quantitative yield from tellurium tetrachloride and mesityl oxide. The reaction of tellurium tetrachloride and acetone in the presence of sodium hydrogen carbonate gives only acetonyl tellurium trichloride and diacetonyl tellurium dichloride5. 

To a refluxing solution of 4 g (0.033 mol) of 4,6-octadiyn-l-ol and 21 g (0.10 mol) of dicyclohexylcarbodiimide in 200 mL of absolute ether, a solution of 1.7 g of crystalline phosphoric add in 100 mL (110 g, 1.41 mol, 43 x molar excess) of dimethyl sulfoxide is added dropwise. After an additional heating for 4 h, 100 mL of 4 N sulfuric acid is added. The precipitated crystals of A/,A/ -dicyclohexylurea are filtered with suction and washed with ether. The filtrate is washed until neutral with a solution of sodium hydrogen carbonate. The dried ether solution is evaporated, and the residue is distilled at 60 °C at 0.001 mm of Hg to give a 73% yield of 4,6-octadiynal as a colorless oil. 

Demethoxycarbonylation of dimethyl l-cyano-3,3-dimethylcyclopropane- ra x-l,2-dicarb-oxylate (22) by treatment with 2 molar equivalents of lithium chloride, water and sodium hydrogen carbonate in dimethyl sulfoxide at 165°C for 30 minutes affords a 2 1 mixture of methyl cis- and fran.9-2-cyano-3,3-dimethylcyclopropanecarboxylate (23) in 89% yield. A considerable increase in stereospecificity of the demethoxycarbonylation is attained by adding a large excess of lithium chloride and water which leads to a cisjtrans product ratio of 10 1. 

Calculate the volume of carbon dioxide gas evolved, measured at room temperature and pressure, when 7,8 g of sodium hydrogen carbonate is heated, The molar volumeof a gas is 24 dm mof at the temperature and pressure of the experiment. 

Anhydrous gaseous or Hquid hydrogen sulfide is practically nonacidic, but aqueous solutions are weakly acid. The for the first hydrogen is 9.1 X 10 at 18°C for the second, is 1.2 x 10 . Reaction of hydrogen sulfide with one molar equivalent of sodium hydroxide gives sodium hydrosulfide with two molar equivalents of sodium hydroxide, sodium sulfide forms. Hydrogen sulfide reacts with sodium carbonate to produce sodium hydrosulfide... 

Numerous methods for the synthesis of salicyl alcohol exist. These involve the reduction of salicylaldehyde or of salicylic acid and its derivatives. The alcohol can be prepared in almost theoretical yield by the reduction of salicylaldehyde with sodium amalgam, sodium borohydride, or lithium aluminum hydride by catalytic hydrogenation over platinum black or Raney nickel or by hydrogenation over platinum and ferrous chloride in alcohol. The electrolytic reduction of salicylaldehyde in sodium bicarbonate solution at a mercury cathode with carbon dioxide passed into the mixture also yields saligenin. It is formed by the electrolytic reduction at lead electrodes of salicylic acids in aqueous alcoholic solution or sodium salicylate in the presence of boric acid and sodium sulfate. Salicylamide in aqueous alcohol solution acidified with acetic acid is reduced to salicyl alcohol by sodium amalgam in 63% yield. Salicyl alcohol forms along with -hydroxybenzyl alcohol by the action of formaldehyde on phenol in the presence of sodium hydroxide or calcium oxide. High yields of salicyl alcohol from phenol and formaldehyde in the presence of a molar equivalent of ether additives have been reported (60). Phenyl metaborate prepared from phenol and boric acid yields salicyl alcohol after treatment with formaldehyde and hydrolysis (61). 

L. Michaelis has reported also a combination of veronal and acetate buffers which, due to the addition of an appropriate amount of sodium chloride, have the same ionic strength as a salt solution isotonic with blood. The original solution is 1/7 molar with respect to sodium acetate and the sodium salt of veronal, 500 c.c. of solution (in carbon dioxide-free water) containing 9.714 g.-of sodium acetate (CH3C00Na-3H20) and 14.714 g. of the veronal salt. Five c.c. portions of this solution are treated with 2 c.c. of an 8.5% NaCl solution, with a c.c. 0.1 N HCl, and with (18 — a) c.c. of water. The following table shows how o and pH (hydrogen electrode 25°) are related. 

Sodium hydroxide is one of the bases commonly used in the laboratory. However, it is difficult to obtain solid sodium hydroxide in a pure form because it has a tendency to absorb water from air, and its solution reacts with carbon dioxide. For these reasons, a solution of sodium hydroxide must be standardized before it can be used in accurate analytical work. We can standardize the sodium hydroxide solution by titrating it against an acid solution of accurately known concentration. The acid often chosen for this task is a monoprotic acid called potassium hydrogen phthalate (KHP), for which the molecular formula is KHC8H4O4 (molar mass = 204.2 g). KHP is a white, soluble solid that is commercially available in highly pure form. The reaction between KHP and sodium hydroxide is... 

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