Reagent dropper

Each student should be provided with a solid wooden stand housing a set of reagents in 30 ml or, preferably, 60 ml bottles. The following are used in the author s laboratory. Some may prefer to have the Ammonia solution, cone, in a T.K. bottle, and the dilute mineral acids in the reagent bottles fitted with reagent droppers. Others may like to have the Hydrochloric acid, dil. of 2-5-3m strength. These are questions of personal preference, and the decision will rest with the teacher. 

Reagent Bottles Fitted with Reagent Droppers (Fig. II. 14a or b)... 

Wash bottles For most work in semimicro analysis a 30 or 60 ml glass stoppered bottle is a suitable container for distilled water the latter is handled with a reagent dropper. Alternatively, a bottle carrying its own dropper (Fig. II. 14a or b) may be used. A small conical flask (25 or 50 ml) may be used for hot water. For those who prefer wash bottles, various types are available (Fig. 11.19) a is a 100 or 250 ml flat-bottomed flask with a jet of 0-5-1 mm diameter, and is mouth-operated b is a hand-operated wash bottle (flask, 125 ml rubber bulb, 50 ml) c is a Pyrex 50 ml graduated wash bottle, and d is a polythene bottle, from which the wash solution can be obtained by squeezing. 

If, for some reason, transfer of the precipitate is essential, a wash liquid or the reagent itself is added, the mixture vigorously stirred and the resulting suspension transferred to a reagent dropper, and the contents of the latter ejected into the other vessel if required, the liquid is removed by centrifugation. 

If reaction does not occur when a little allyl bromide is first introduced, further addition must be discontinued until the reaction has commenced. Remove 2-3 ml. of the Grignard solution with a dropper pipette, add about 0-5 ml. of allyl bromide and warm gently to start the reaction after this has reacted well, add the solution to the main portion of the Grignard reagent. 

The dropper shown in Figure 81, II, has a small bulb so that for maximum uptake liquid does not enter the rubber teat reagent solutions are then less likely to be contaminated. The capillary tube... 

Do not insert droppers into reagent bottles. Pour a small amount of the chemical into a beaker. 

Much time will be saved if each of the solvents (water, ether, 5% sodium hydroxide, 5% sodium hydrogen carbonate and 5% hydrochloric acid) be contained in a 30- or 60-ml reagent bottle fitted with a ground-in calibrated dropper. 

With a micropipette or dropper, add 0.1 ml of nitric acid, reagent grade to the silver composition in the bottle. 

The reagents 1% Br2in cyclohexane, 1% aqueous KMn04, and concentrated H2S04 are available in dropper bottles. 

The following solutions should be placed in dropper bottles. (100 mL) Acetone (reagent grade)... 

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