Glassware Precautions and Cleaning

Brown stains of manganese dioxide that are left in the glassware can generally be removed by rinsing the apparatus with a 30% (4 M) aqueous solution of sodium bisulfite, NaHS03. If this fails, wash the equipment with water and then add a small amount of 6 M HCl. This must be done in a hood, since chlorine gas is evolved try this technique only after obtaining permission from your instructor. 

Your laboratory kit contains standard-taper glassware with ground-glass joints. 

Before the advent of standard-taper glassware, we had to bore corks or rubber stoppers to fit each piece of equipment, and the glass apparatus was assembled by connecting the individual pieces of equipment with glass tubing. This was not only time-consuming, but many chemicals reacted with and/or were absorbed by the 

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