Chemical lecture experiments . ntrated sulphuric acid # ormercury. By means of the three-way cock the gas may beconducted into the flue until desired and then by turning thecock may be passed through the sulphuric acid into anyapparatus. Though no difficulty should be experienced in properlyturning the three-way cock it is easy to note by the bubblingin the sulphuric acid bottle whether or no the gas is properly 80 CHLORINE 81 directed. In case the cock should be so turned as to cutthe exit of the gas off entirely, the rise of the sulphuric acidor mercury in the safety-funnel as well as the ab
Chemical lecture experiments . ntrated sulphuric acid # ormercury. By means of the three-way cock the gas may beconducted into the flue until desired and then by turning thecock may be passed through the sulphuric acid into anyapparatus. Though no difficulty should be experienced in properlyturning the three-way cock it is easy to note by the bubblingin the sulphuric acid bottle whether or no the gas is properly 80 CHLORINE 81 directed. In case the cock should be so turned as to cutthe exit of the gas off entirely, the rise of the sulphuric acidor mercury in the safety-funnel as well as the absence ofbubbles in the gas washing-bottle containing water will beimmediately noticed. The stopper used in the generatingflask should be of rubber, and both the safety-tube and the glass elbow should fit snuglyinto the respective holes. Chlo-rine will in course of time attackrubber and render it hard andunsuited for use. By coatingthe under side of the stopperwith collodion just before insert-ing it in the flask, the action of. ^=a=^a T Fig. 39 the chlorine may be very much lessened. The water in thegas washing-bottle removes traces of hydrochloric acid car-ried over, and the gas issuing from the sulphuric acid bottleis, accordingly, quite pure. In case a flue is not at hand,the warste gas issuing from the stem of the three-way cockshould be conducted through a glass tube into potassium orsodium hydroxide solution. Mn02 + 4 HC1 = MnCl2 + 2 H20 +C12. Apparatus (Fig. 39) ; 2 1. flask ; two gas washing-bottles; three-way cock ; safety-tube ; 2-holed rubber stopper ; coarsely pulverizedMn02. G 82 CHEMICAL LECTURE EXPERIMENTS 2. By the action of sulphuric acid on a mixture of sodiumchloride and manganese dioxide. — Instead of acting directlyon manganese dioxide with hydrochloric acid, the acid maybe prepared in the presence of manganese dioxide, where itis immediately oxidized with the liberation of apparatus used is shown in Fig. 39. One hundred grams of finely pulve
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