Tinctures dioxide

Add 0.2 cc. of litmus tincture to 100 cc. of distilled water, and boil for some time in a platinum dish to free it from carbon dioxide. The violet color of the liquid so obtained must change to red on the addition of 0.05 cc. of decinormal hydrochloric acid or must pass into a pure blue color on the addition of 0.05 cc. of decinormal potassium hydroxide. 

Solutions are everywhere around us. Most of the gases, liquids, and solids we see are mixtures of at least one substance dissolved in another. There are different types of solutions. The air we breathe is a solution that is primarily oxygen and nitrogen gases. Carbon dioxide gas dissolved in water makes carbonated drinks. When we make solutions of coffee or tea, we use hot water to dissolve substances from coffee beans or tea leaves. The ocean is also a solution, consisting of many salts such as sodium chloride dissolved in water. In your medicine cabinet, the antiseptic tincture of iodine is a solution of iodine dissolved in ethanol. 

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