Question

I've recently conducted an experiment where I reacted zinc with sodium hydroxide to form sodium zincate (Na2ZnO2). However, I'm having trouble comprehending why sodium zincate has the composition Na2ZnO2. Can someone explain the chemical reactions and principles that lead to this specific composition? Additionally, what factors influence the stoichiometry of this reaction, and how does it relate to the properties of sodium zincate?

Answer 1

Sodium zincate has the composition Na2ZnO2 because zinc metal reacts with sodium hydroxide and water to form the complex ion Zn(OH)42- in sodium zincate, with the reaction also producing hydrogen gas. Factors such as concentration and temperature affect the stoichiometry and properties of sodium zincate.

Step-by-step explanation:

The composition of sodium zincate as Na2ZnO2 is due to the chemical reaction between zinc metal and sodium hydroxide. This reaction occurs because zinc is a reactive metal that can react with the hydroxide ion (OH-) to form zincate. The balanced chemical reaction is:

Zn(s) + 2NaOH(aq) + 2 H2O(l) → Na2Zn(OH)4 (aq) + H2(g)

In this reaction, zinc displaces hydrogen from water (H2O) in the presence of NaOH to form sodium zincate and release hydrogen gas (H2). By adjusting conditions like the concentration of NaOH, we can control the stoichiometry of the reaction, which determines the properties of the resulting sodium zincate. Factors like concentration, temperature, and the reactivity of the metals can influence the stoichiometry.