Thermal decomposition products of hydrated magnesium nitrate

Steps:

• Hydrated magnesium nitrate, Mg(NO3)2·6H2O, first undergoes dehydration upon heating, releasing water vapor (steam).
• The anhydrous Mg(NO3)2 then decomposes: 2Mg(NO3)2 → 2MgO + 4NO2 + O2.
• Products are magnesium oxide (MgO), nitrogen dioxide (NO2), oxygen (O2), and steam (H2O).
• Dinitrogen monoxide (N2O) does not appear in the reaction.

Why A is correct:

• Dinitrogen monoxide (N2O) forms in the decomposition of ammonium nitrate (NH4NO3 → N2O + 2H2O), not magnesium nitrate.

Why the others are wrong:

• B: Magnesium oxide is the solid residue from nitrate decomposition.
• C: Oxygen is a gaseous product in the balanced equation.
• D: Steam is released during dehydration of the hydrate.

Final answer: A