Solution alkalinity

Then cool the reaction-mixture, filter it at the pump, leaving a black residue of selenium, and wash out the flask twice with 2x5 ml. of acetic acid, passing the washings also through the filter. Dilute the united filtrates with water, and make the solution alkaline with 10% aqueous sodium hydroxide, which precipitates the camphorquinone. Cool, filter off the yellow camphorquinone at the pump, wash with water and drain thoroughly. 

To isolate the triphenylguanidine, dilute the residue in the flask with 50 ml. of water, add 2-3 g. of decolourising carbon, warm, and filter. Cool the solution in ice, and filter oflF the hydrochloride at the pump. Dissolve it in the minimum volume of hot water, render the solution alkaline with sodium hydroxide, and allow to cool. Filter off the free base (triphenylguanidine), and recrystallise it from alcohol it separates in colourless crystals, m.p. 144°, The yield is 3 g. 

In a 1 htre round-bottomed flask, provided with an air condenser, place a mixture of 25 g. (26 ml.) of pure dimethylanihne, 10 g. of Michler s ketone (4 4 tetramethyldiaminobenzophenone) and 10 g. (6 ml.) of phosphorus oxychloride. Heat on a boding water bath for 5 hours. Add about 150 ml. of water and sufificient sodium hydroxide solution to render the solution alkaline. Calculate the quantity of sodium hydroxide required upon the basis of the hydrolysis product derived from the phosphorus oxychloride ... 

Hydrolysis of a sulphonamide. Mix 2 g. of the sulphonamide with 3-5 ml. of 80 per cent, sulphuric acid in a test-tube and place a thermometer in the mixture. Heat the test-tube, with frequent stirring by means of the thermometer, at 155-165° until the solid passes into solution (2-5 minutes). Allow the acid solution to cool and pour it into 25-30 ml. of water. Render the resulting solution alkaline with 20 per cent, sodium hydroxide solution in order to liberate the free amine. Two methods may be used for isolating the base. If the amine is volatile in steam, distil the alkaline solution and collect about 20 ml. of distillate extract the amine with ether, dry the ethereal solution with anhydrous potassium carbonate and distil off the solvent. If the amine is not appreciably steam-volatile, extract it from the alkaline solution with ether. The sulphonic acid (as sodium salt) in the residual solution may be identified as detailed under 13. 

Miyatake and Yashikawa have prepared several 2,4-disubstituted thiazoies in fairly low yield (16 to 40%) by the action of a-mercaptoketones (226) on nitriles (227) (Scheme 118 and Table IT38). The reaction was carried out in benzene solution at 0 C by passing a current of dry hydrogen chloride through the mixture. After 3 hr the mixture was filtered and washed with benzene. When the resins had been removed and the remaining solution alkalinized, the product was extracted. 

Make solution alkaline with NaHC03 and titrate excess I2 with standard arsenite solution. HPH2O2/4 = 16.499... 

Plating Bath Purification. Purification, often needed once a plating bath is made, is used periodically to maintain the plating solutions. Alkaline ziac plating solutions are sensitive to a few mg/L of heavy-metal contamination, which can be precipitated usiag sodium sulfide and filtered out. 

Common bases, whieh render aqueous solutions alkaline. 

Hence 0.771 - 0.059161og,o(10 ) = 0.771 - 1.301 = -0.530 V Thus by making the solution alkaline the sign of has been reversed and the susceptibility of Fe (aq) to oxidation (i.e. its reducing power) enormously increased. This is why white, precipitated Fe(OH)2 and FeCOs are rapidly darkened by aerial oxidation and why Fe in alkaline solution will reduce nitrates to ammonia and copper(II) salts to metallic copper. 

An alternative purification can be effected by dissolving the reaction product in water. The ester base is liberated by rendering the clarified aqueous solution alkaline. Removal of the base from the alkaline solution is achieved by extraction with a Suitable solvent such as benzene or ether. The pure hydrochloride of diethylaminoethyl 2-chloro-4-aminobenzoate Is then precipitated from the dried extract by the addition of dry hydrogen chloride. After removal by filtration and recrystallization from ethanol it is found to have a melting point of 173° to 174°C. 

Batteries using an alkaline solution for electrolyte are commonly called alkaline batteries. They are high-power owing to the high conductivity of the alkaline solution. Alkaline batteries include primary batteries, typical of which are alkaline-manganese batteries, and secondary batteries, typical of which are nickel-cadmium and nickel-metal hydride batteries. These batteries are widely used. 

Formazans are stable in alkaline solution. Alkaline hydrolysis of functionalities on formazans such as nitriles, esters, and amides leads to the acids (Section 7.3.1.1). The case of 3-nitroformazans (198) is unique. Reaction with hydroxide ion gives 3-hydroxy formazan (199) which can be readily oxidized to the tetrazolium betaine. In the presence of hydrosulfide, a reduction of the nitro group takes place giving 3-aminoformazan (200) with traces of the 3-mercaptoformazan (201), which by contrast is the main product when ammonium polysulfide is used (Scheme 30).45,346... 

Acid solution + alkaline solution -> water + salt... 

Theory Selenium is very toxic and its contamination is usually controlled by an absorptiometric method after destruction of the organic compound with fuming nitric acid. The latter converts selenium (Se) as selenous acid (H2Se03), which on subsequent treatment with 3,3 -diaminobenzidinc under controlled experimental parameters, results into the formation of a highly coloured compound known as 3,4-diaminophenylpiazselenol. The latter is consequently extracted with toluene after making the aqueous solution alkaline, and the colour compared with a standard prepared likewise from a known amount of selenium. The various reactions involved may be expressed as follows ... 

Materials Required Solution (1) dilute 1 volume of solution (3) to 200 volumes with a 0.005% w/v solution of N-phenylcarbazole (internal standard) in toluence 10 ml Solution (2) (add 5 ml of DW to 0.1 g of bromopheneramine maleate sample, make the resulting solution alkaline with 13.5 M ammonia, add 2.5 ml of toluene, shake for 5 minutes, centrifuge and use the upper layer) solution (3) (prepare it exactly in the same manner as solution- 2 but using the internal standard solution in place of toluene) Solution (4) (dissolve 10 mg of bromopheneramine maleate BPCRS in 5 ml of DW, make alkaline with 13.5 M ammonia, add 2.5 ml of toluene, shake for 5 minutes, centrifuge and dilute 1 volume of the upper layer to 20 volumes with toluene) ... 

Brashear s silvering solution (alkaline ammoniacal silver oxide containing glucose) or residues therefrom should not be kept for more than 2 hours after preparation, since an explosive precipitate forms on standing [1], The danger of explosion may... 

Technetium metal can be electrodeposited from an acidic solution of pertechnetate using a platimun, nickel or copper cathode. Electrolysis of neutral, unbuffered solutions, alkaline solutions, and sulfuric acid solutions lower than 2 N yield a black deposit of hydrated TcOj The current efficiencies are generally poor but the deposition is reasonably quantitative. The deposition requires the application of relatively negative cathode potentials and is therefore non-selective. Polaro-graphy indicates that the overpotentials for the evolution of hydrogen on technetium are rather low hence, electrolysis from acidic media will always include concurrent discharge of hydrogen . ... 

Amines, like ammonia, are weak bases (see p. 31) and dissociate to a slight extent in aqueous solution. In the reaction, the non-bonded pair (lone pair) of electrons on the nitrogen atom in the amine molecule accepts a proton (hydrogen ion) from the water molecule, thus generating alkylammonium ions and hydroxide ions. The latter ions make the solution alkaline. For example CHjNH aq) H20(l) CH3NH3 (aq) -r OH (aq)... 

The HCO amount listed in table 8.28 actually represent carbonate alkalinity, calculated neglecting CO ". The alkalinity [Aik] of a solution represents its capacity to neutralize strong acids in solution. Alkalinity can be defined as the sum of equivalents of all species whose concentrations depend on the concentration of ions in solution, minus the concentration of ions in solution. For a solution containing borates and carbonates, alkalinity can be expressed as... 

Fe(OH)2 Magnetite Goethite, Lepidocrocite, Magnetite, Maghemite Oxidation N2 Alkaline solution Alkaline solution... 

Colorless gas pungent suffocating odor human odor perception 0.5 mg/m hquefies by compression at 9.8 atm at 25°C, or without compression at -33.35°C (at 1 atm) sohdifies at -77.7°C critical temperature and pressure, 133°C and 112.5 atm, respectively vapor density 0.59 (air l) density of liquid ammonia 0.677 g/mL at —34°C dielectric constant at —34°C is about 22 extremely soluble in water solution alkaline pKa 9.25 in dilute aqueous solution at 25°C the gas does not support ordinary combustion, but bums with a yellow flame when mixed in air at 16— 27% composition. 

Soft white crystalline powder hexagonal density 2.34 g/cm shghtly bitter taste loses water when heated at elevated temperatures (580°C) shghtly soluble in water Ksp 1.2xl0 i4 aqueous solution alkaline soluble in glycerol and acids insoluble in alcohol. 

Lemon-yellow rhombohedral crystals density 2.732 g/cm melts at 968°C very soluble in water, 63 g/lOOmL at 20°C aqueous solution alkaline insoluble in alcohol. 

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