There will be no reaction. Sodium is more reactive than magnesium. So magnesium cannot displace sodium from its compound. Thus no reaction occurs. —Gt. read more
Actually, magnesium reacts with molten sodium hydroxide to make magnesium oxide, sodium and hydrogen after this reaction: 2Mg+2NaOH=2Na+2MgO+H2. This happens because the enthalpy of formation for magnesium oxide (−601.6 kJ/mol) is higher than that of sodium hydroxide (−425.93 kJ/mol), so it is thermodynamically favorable to have sodium and magnesium oxide and hydrogen. read more
When the solid powders of magnesium metal and NaOH are mixed, vigorous reaction takes place to produce sodium metal as per the following equation 2Mg + 2NaOH --> 2MgO + 2Na + H2 The reaction is highly exothermic to ignite hydrogen gas. read more