How to distinguish aluminum sheet from magnesium sheet?
magnesium sheet will react with alkali.
put them into acid and observe bubble's generating speed, the quicker one is magnesium sheet.
put them into NaOH, the one generating bubble is aluminum sheet, because aluminum sheet can react with it, generating hydrogen. Or light them in the air, the burning one is magnesium sheet.
seperately put aluminum sheet and magnesium sheet into NaOH solution, the one generating bubble is aluminum sheet, because aluminum sheet will react with strong base , generating hydrogen.
put two sheets into excess NaOH. The one that reacts with NaOH, generating sediment, is magnesium sheet,(sediment, but Al(OH)3 is amphoteric:Mg(OH)2) another one without sediment is aluminum sheet(in fact, there is sediment Al(OH)3, but it will react with alkali,)
