Question

Magnesium ribbon is rubbed before burning because it has a coating of (a) basic magnesium carbonate (b) basic magnesium oxide (c) basic magnesium sulphide (d) basic magnesium chloride

Answer 1

Answer: option(a) basic magnesium carbonate is correct

Answer 2

Magnesium ribbon is wrapped and cleaned before burning because it has a coating of basic magnesium oxide.

• Magnesium is a highly reactive metal placed at high position in the reactivity order series.

• It reacts with the oxygen of the air to for a layer of white coloured magnesium oxide.

• This layer of of magnesium oxide prevents direct contact of the inner layer of the magnesium metal with air and prevents burning.

• Hence , this layer has to be cleaned carefully with a sandpaper before burning such that the magnesium metal can be burnt efficiently.

• Rubbing of magnesium metal before burning also helps to remove the surface impurities and allow total burning of the metal.

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