Question

why should meganisum ribbon should be change before burning in air ​

Answer 1

Answer:

the magnesium ribbon should be clean before burning because there is a layer of magnesium oxide due to the presence of air which hinders its burning therefore, magnesium ribbon should be cleaned before burning

Answer 2

Answer :

Magnesium is a highly reactive metal. When exposed to air for a long time it gets coated with the layer of oxide which is physically and mentally stable and therefore, partly masks the reactivity of magnesium. The oxide coating does not burn when a flame is brought in contact with the metal. Therefore, the surface should be cleaned, with a sandpaper before burning the magnesium ribbon in air.