Solutions used

NH4)3Moi2PO40 H2O. The bright yellow precipitate formed from a phosphate, am monium molybdate and HNO3 in solution. Used as a test for phosphates. 

Schweizer s reagent The dark blue solution obtained by dissolving Cu(OH)2 in concentrated ammonia solution. Used as a solvent for cellulose, the cellulose is precipitated on acidification. Used in the cuprammonium process for the manufacture of rayon. 

Sorbitol is manufactured by the reduction of glucose in aqueous solution using hydrogen with a nickel catalyst. It is used in the manufacture of ascorbic acid (vitamin C), various surface active agents, foodstuffs, pharmaceuticals, cosmetics, dentifrices, adhesives, polyurethane foams, etc. 

The theoretical treatments of Section III-2B have been used to calculate interfacial tensions of solutions using suitable interaction potential functions. Thus Gubbins and co-workers [88] report a molecular dynamics calculation of the surface tension of a solution of A and B molecules obeying Eq. III-46 with o,bb/ o,aa = 0.4 and... 

Plot the scaling behavior for the surface tension of polystyrene solutions using Eq. III-64, for N = 1,000 and T from zero to Tc- Now plot the behavior for T = 0.87 for N = 100-1000. Comment on the influence of polymers on surface tension. 

Bardeen C J and Shank C V 1993 Femtosecond electronic dephasIng In large molecules In solution using mode suppression Chem. Phys. Lett. 203 535-9... 

Kneipp K, Kneipp H, Deinum G, Itzkan I, Dasari R R and Feld M S 1998 Single-molecule detection of a cyanine dye in silver colloidal solution using near-infrared surface-enhanced Raman scattering App/. Spectrosc. 52 175-8... 

Ikemiya N, Miyaoka S and Hara S 1994 Observation of the Cu(1 1) adlayer on Au(111) in a sulfuric acid solution using atomic force microscopy Surf. Sc/. 311 L641-8... 

Distil the filtered ethereal solution, using a 100 ml. flask fitted with a dropping-funnel and a side-arm for the condenser observe all the normal precautions for ether distillation (p. 162) and run the ethereal solution into the flask as fast as the ether distils over. When all the ether has distilled off, detach and cool the flask, when the oily colourless residue of saligenin will rapidly crystallise. Weight of product, 5-0 g. m.p. 75-82°. Recrystallise either from a mixture of benzene and petroleum (b.p. 60-80°), or from a minimum of water, allowing the stirred aqueous solution to cool to 65-70° before chilling. The dry crystalline saligenin has m.p. 85-86°. 

Reactions of Picric Acid, (i) The presence of the three nitro groups in picric acid considerably increases the acidic properties of the phenolic group and therefore picric acid, unlike most phenols, will evolve carbon dioxide from sodium carbonate solution. Show this by boiling picric acid with sodium carbonate solution, using the method described in Section 5, p. 330. The reaction is not readily shown by a cold saturated aqueous solution of picric acid, because the latter is so dilute that the sodium carbonate is largely converted into sodium bicarbonate without loss of carbon dioxide. 

It should be emphasised that the calcium chloride solution used in testing for acids is of Reagent concentration (p. 524) throughout. 

Reaction with sodium carbonate. Boil about 0 5 g. of 0- and of />-nitrophenol in turn with Na2C03 solution, using the method described in Section 5, p. 336, and note the evolution of CO2. 

The molecular weight of many carboxylic acids which arc freely soluble in cold water (i.e., chiefly the aliphatic acids) can readily be obtained by titrating a known weight of the acids in aqueous solution with standard sodium or potassium hydroxide solution, using phenolphthalein as an indicator. To avoid the use of unduly large quantities of the acid, it is advisable to use Mj2 caustic alkali solution, and in order to obtain a sharp end>point, this alkali solution... 

Cool the flasks in cold water, and then titrate the contents of each with /i/.t a()H solution, using phenolphthalein as an indicator. Shake the contents of the flask A repeatedly during the titration in order to keep the fine crystals of acetanilide dispersed in the aqueous solution. 

Transfer 25 ml. of this dilute solution by means of a pipette to a conical flask, and add similarly 50 ml. of Ml 10 iodine solution. Now-add 10% sodium hydroxide solution until the liquid becomes pale yeilow in colour, and allow the solution to stand, with occasional shaking, at room temperature for at least 10 minutes. Then acidify with dilute hydrochloric acid (free from chlorine) in order to liberate the remaining iodine. Titrate the latter w ith Mho sodium thiosulphate solution, using starch as an indicator in the usual way. 

From the above equations, it will be seen that i ml. of the M/10 iodine solution used in the oxidation is equivalent to 0-00150 g. of formaldehyde. 

With the aid of a small pipette or a fine-bore dropping-tube (Fig. 30, p. 60), add about 4 drops of the filtered enzyme solution to the amine acetate solution. Using another dropping-tube add i drop of 20 volume hydrogen peroxide solution and shake well. Note the colour change which takes place. 

In the isolation of organic compounds from aqueous solutions, use is frequently made of the fact that the solubility of many organic substances in water is considerably decreased by the presence of dissolved inorganic salts (sodium chloride, calcium chloride, ammonium sulphate, etc.). This is the so-called salting-out effect. A further advantage is that the solubility of partially miscible organic solvents, such as ether, is considerably less in the salt solution, thus reducing the loss of solvent in extractions. 

To obtain optically pure I- and daec.-octyl alcohols, steam distil the respective esters with 30 per cent, sodium hydroxide solution use the proportions 1 mol of ester to 2 mols of sodium hydroxide. Separate the alcohols from the steam distillate, dry over anhydrous potassium carbonate, and distil under diminished pressure. Both samples boU at 86°/20 mm. (9) and have the following rotations ... 

To determine the exact peroxide content of benzoyl peroxide (and of other organic peroxides) the following procedure may be employed. Place about 0 05 g. of the sample of peroxide in a glass-stoppered conical flask add 5-10 ml. of acetic anhydride (A.R. or other pure grade) and 1 g. of powdered sodium iodide. Swirl the mixture to dissolve the sodium iodide and allow the solution to stand for 5-20 minutes. Add 50-75 ml. of water, shake the mixture vigorously for about 30 seconds, and titrate the liberated iodine with standard sodium thiosulphate solution using starch as indicator. 

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