Chemical lecture experiments . sk will be found to be rich in ozone, which instantly turns blue a moistened pieceof potassium iodide starch paper. Asit is desirable to pass the ozonized airthrough certain tubes, the flask shouldbe selected with a neck small enoughto be fitted with a two-holed rubberstopper which has two glass elbowsthrust through it, the end of one ofthe elbows extending 10 or 12 cm. be-low the bottom of the stopper. Whenwater from the faucet is allowed torun slowly through the shorter elbow,it gradually fills the flask, driving theozone out through the elbow whoseend is neare
Chemical lecture experiments . sk will be found to be rich in ozone, which instantly turns blue a moistened pieceof potassium iodide starch paper. Asit is desirable to pass the ozonized airthrough certain tubes, the flask shouldbe selected with a neck small enoughto be fitted with a two-holed rubberstopper which has two glass elbowsthrust through it, the end of one ofthe elbows extending 10 or 12 cm. be-low the bottom of the stopper. Whenwater from the faucet is allowed torun slowly through the shorter elbow,it gradually fills the flask, driving theozone out through the elbow whoseend is nearest the bottom. As rubberrapidly destroys ozone, the ozonized air must be drawnfrom below the rubber stopper (Fig. 14). The formationof ozone in this manner is dependent on the temperature,and at 20° it is not uncommon to have very stronglyozonized air in the flask at the end of half an large bottle can be used instead of the flask. Flask, 2 or more 1. ; cork and tubes (Fig. 14) ; sticks of P 4 ; Kl-starch Fig. 14 33. From the slow combustion of ether in air. — Whenether is burned in air under certain conditions, a product isformed giving the ozone reactions, and is commonly calledozone, though its nature is not thoroughly understood. OZONE 35 Two cubic .centimeters of ether are poured into a 200 and well shaken. When a platinum wire, which hasbeen heated in a Bunsen flame and allowed to cool until theglow has disappeared, is lowered into the jar containingthe mixture of ether vapor and air, a partial combustiontakes place. A glass rod heated till the flame begins to becolored may be substituted for the platinum wire. Thegaseous contents of the cylinder will give a decided ozonereaction when a strip of iodo-starch paper is introduced. 200 cc. cylinder ; platinum wire ; iodo-starch paper ; ether. PROPERTIES 34. Iodo-starch paper (potassium iodide and starch).— Ozone acts upon potassium iodide and liberates iodine. Thefree iodine immediately
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