question_answer

  The way by which metals like sodium, magnesium and iron react with air and water is an indication of their relative positions in the 'reactivity series'? Is this statement true? Justify your answer with examples.

Answer:

                  Yes, this statement is true. Example 1 Reaction with air (i) Sodium even on exposure to air reacts vigorously with oxygen, i.e., burns to form sodium oxide (ii) Magnesium, on heating over flame reacts to form magnesium oxide (iii) Iron, on heating reacts with oxygen to give iron II III oxide and hydrogen gas, but it does not burn. (3) Example 2 Reaction with water In the same way, sodium react violently with cold water, magnesium with boiling water while red hot iron  reacts with  steam  to  produce  their corresponding   oxides   or   hydroxides   and hydrogen gas. This, the order of reactivity is Na>Mg>Fe   (2)