Funnel stopper

From this solution, prepare 25.0 mL of a 0.00025 M solution of iodine in water. Pour this entire solution into a 125-mL separatory funnel. Stopper the funnel. 

S)-2-Chloropropan-l-ol. Into a 2-L, three-necked, round-bottomed flask equipped with a mechanical stirrer, 250 mL dropping funnel, stopper (Note l) and an efficient reflux condenser fitted with a calcium chloride drying tube, is placed 9.1 g (0.24 mol) of lithium aluminum hydride, 400 mL of dry diethyl ether is added with caution. The slurry is cooled in an ice bath and a... 

Equip a second stopcocked flask (2000 mL) with the Schlenk-type filter funnel. Stopper the upper joint of the funnel, connect its side-arm stopcock to a source of dry nitrogen, and the side-arm stopcock of the flask to a pump inlet. 

Place a drop of the test solution together with a few milligrams of lead dioxide and acetic acid in the apparatus of Fig. 11.56 and close the tube with the funnel stopper carrying a piece of filter paper which has been impregnated with the reagent and dried. Warm the apparatus gently. A circular red spot is formed on the yellow test paper. 

The spot-test technique is carried out as follows. Place a drop of the test solution in the tube of Fig. 11.56, add 1-2 drops 20 per cent sodium hydroxide solution and a few milligrams of Devarda s alloy. Place a watch glass with a drop of p-nitrobenzene-diazonium chloride reagent (for preparation, see under Ammonium, Section III.38, reaction 8) on its underside upon the funnel stopper. Heat the apparatus gently for a short time. Add a tiny fragment of calcium oxide to the drop of the reagent a red ring forms within 10-15 seconds. 

Dissolve 3 g of the mixture in 30 mL of ether and transfer the mixture to a 125-mL separatory funnel using a little ether to complete the transfer. Add 10 mL of water and note which layer is organic and which is aqueous. Add 10 mL of a 10% aqueous solution of sodium bicarbonate to the funnel. Stopper the funnel and cautiously mix the contents. Vent the liberated carbon dioxide and then shake the mixture thoroughly with frequent venting of the funnel. Allow the layers to separate completely and then draw off the lower layer into a 50-mL Erlenmeyer flask (labeled Flask 1). What does this layer contain ... 

Stock solutions of 5% APCD (Fisher Scientific) are made daily in distilled deionized water and extracted at least three times with MIBK. Seawater samples are stored in acid-soaked, deionized, water-rinsed polypropylene bottles. All reagents used were reagent grade or the highest grade readily available. Polypropylene graduated cylinders and separatory funnel stoppers and Teflon stopcocks were used in all cases. 

Now the vacuum hose is disconnected and the Buchner funnel, stopper and all, is pulled from the filtering flask. All of the filtered solvent is poured back into the Erlenmeyer flask it came from. It is returned to the HCl source for more bubbling. The Buchner funnel is put back into the top of the filtering flask. It still contains the filter cake of... 

Procedure, (a) The apparatus shown on page 54 (Fig. 26) is used. It is charged with a drop of the test solution and a few particles of lead peroxide and acetic acid, or a few drops of chromic acid. The apparatus is closed with the funnel stopper and filter paper moistened with fluorescein solution is laid over the funnel. The apparatus is gently warmed, and, according to the amount of bromine present, a circular red fleck is formed more or less rapidly on the yellow test paper. The apparatus of Fig. 27 may alternatively be used. 

To the separatory funnel add 5 mL of isatin solution and 10 mL of ferric sulfate-sulfuric acid solution. Stopper and shake for 2 min 15 s. Allow the phases to separate and draw off the lower H2SO4 layer into a 50-mL volumetric flask. Add 10 mL of H2SO4 to the separatory funnel, stopper, and shake for 30 5 s. Again draw off the lower H2SO4 layer into the 50-mL volumetric flask containing the first extract. Dilute to volume with H2SO4 and mix. 

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