Answer to Question #129181 in General Chemistry for Hadassah

Question

Butane and potassium permanganate is tested. What is the observation and inference?

Answer 1

Butane and Potassium Permanganate Test

Butane can be tested either by using the bromine decolourization test or the Baeyer test. In the bromine decolourization test, a few drops of bromine solution are added in carbon tetrachloride solution. In this case, butane is not supposed to react. In the Baeyer test, bubbling a gas through a cold, dilute, and aqueous potassium permanganate (purple in colour) solution is done. If butane is present, there will be no colour change witnessed.            

           

On the other hand, Potassium permanganate is a strong oxidant and can react with numerous functional groups. When in controlled conditions, potassium permanganate effectively oxides primary alcohols into carboxylic acids. To test Potassium permanganate, dissolve few drops of the compound to be tested in either water of aqueous ethanol. Then add a small percentage of the potassium permanganate dropwise and shake the solution. When the purple colour disappears and a brown precipitate forms, the test tends to be positive.