Question

A shining metal ‘M’, on burning gives a dazzling white flame and changes to a white powder ‘N’.

(a) Identify ‘M’ and ‘N’.

(b) Represent the above reaction in the form of a balanced chemical equation.

(c) Does ‘M’ undergo oxidation or reduction in this reaction? Justify.

Answer 1

(a) Reaction of Magnesium metal:

1. As, it is given that the metal ‘M’ on burning gives the dazzling white flame and also changes to the white powder ‘N’.
2. So, the metal ‘M’ would be Magnesium metal as on the reaction of burning in the air, Magnesium reacts with the Oxygen present in the air and gives the white powder on burning.
3. This Magnesium metal is basically the chemically active one.
4. Hence, the metal ‘M’ : Magnesium burns in the presence of Oxygen to form ‘N’ Magnesium oxide.

(b) The balanced chemical equation for the above reaction would be:

1. Reaction: $\underset{\underset{\text{'}\mathrm{M}\text{'}}{\mathrm{Magnesium}}}{\mathrm{Mg}\left(\mathrm{s}\right)}+\underset{\mathrm{Oxygen}}{{\mathrm{O}}_2\left(\mathrm{g}\right)}\stackrel{∆}{\to }\underset{\underset{\text{'}\mathrm{N}\text{'}}{\mathrm{Magnesium}\mathrm{oxide}}}{\mathrm{MgO}\left(\mathrm{s}\right)}$
2. 

(c) Oxidation of Magnesium:

1. Oxidation is basically the loss of electrons or the increase in the oxidation state of an atom, ion or the molecule.
2. So previously when solid Magnesium was present it's oxidation state was 0 as the element Magnesium was present with not any bond.
3. But, as soon as it burns in the presence of Oxygen forming the Magnesium oxide, it will lose two electrons for getting stable
4. So, the Oxidation state of $\mathrm{Mg}$ in $\mathrm{MgO}$ is $+2$
5. Hence, Oxidation of Magnesium will take place.