ZN (s) + NaOH which gives sodium zincate, together with hydrogen gas.
The compound sodium zincate, together with hydrogen gas, is formed when zinc reacts with excess sodium hydroxide. Zinc is an example of transition metal which demonstrates mild reactivity. Since zinc is amphoteric, it interacts with the evolution of hydrogen gas to form sodium zincate with NaOH. At a temperature near 550 °C, these reactions occur. The reaction is an example of endothermic reaction.
The equation of the reaction is
Zn + 2NaOH → Na2ZnO2 + H2
2Zn(OH)2 + 2 NaOH→ Na2ZnO2 + 3H2O