Okay, so I was one of four people in my AP chemistry class today because of a different AP test most of the class was out forNaturally, we all went to the lab and got to do cool things we wanted toI read instructions and managed to coat several pennies in brass, using a mixture of the two pennies, zinc metal, and sodium hydroxideThis mixture was heated and the pennies were coated in zincThen, the pennies were heated in a flame and the outer zinc layer mixed with the copper already there and presto, the pennies were coated in shiny brassAnyway, when I was all done, I added a little piece of
aluminum foil to the mixture to see if anything would happenIt bubbled violently and released a gas that burned the inside of my noseI\'m just wondering, what exactly did the aluminum react with? I know a reaction is supposed to occur with sodium hydroxide, but is it supposed to be this violent? And it could also have occurred with the copper (II) ion dissolved in solutionAnyone know what happened?The gas evolved was H2 and the bubbles carried along some of the alkaline solution which would account for the burning sensationAluminum placed in NaOH solution is an excellent way to generate small quantities of hydrogen gas and the reaction is vigorousSome of the copper ions might have cleaned the surface of the Al aiding in the attack of the hydroxide ion on the Al metal surfaceEven water will evolve hydrogen with aluminum if the surface is clean2 Al + 6 H2O + 2 NaOH - 3 H2 + 2 NaAl(OH)4Other related question