Question

What will be formed from the reaction: NaOH + Zn $\rightarrow$ ?

• A. Sodium Zincate and Hydrogen gas
• B. Zinc Oxide and Sodium
• C. Sodium Hydride and Zinc
• D. No reaction will occur

Hint:

Amphoteric metals like zinc (Zn) and aluminum (Al) can react with strong bases (like NaOH) to produce a complex salt and hydrogen gas. This is an important property distinguishing them from metals that only react with acids.

Answer 1

The Correct Option is A

Step 1: Understanding the reaction between a base and an amphoteric metal.
The reaction between sodium hydroxide (NaOH), which is a strong base, and zinc (Zn), an amphoteric metal, is a characteristic reaction where the metal reacts with the base to produce a salt and hydrogen gas. Amphoteric metals are elements that can react with both acids and bases. Zinc is a well-known example of an amphoteric metal.
Step 2: Writing the balanced chemical equation.
When zinc reacts with sodium hydroxide solution, it forms sodium zincate (Na₂ZnO₂) and liberates hydrogen gas (H₂). The balanced chemical equation for this reaction is:

 2NaOH(aq) + Zn(s) → Na2ZnO2(aq) + H2(g)
 

Step 3: Evaluate the options.

• Option (a): Sodium Zincate and Hydrogen gas: This matches the products of the reaction, as derived from the chemical equation.
• Option (b): Zinc Oxide and Sodium: This is incorrect. Zinc oxide is not formed, and sodium metal is not a product.
• Option (c): Sodium Hydride and Zinc: This is incorrect. Sodium hydride is not formed, and zinc is a reactant, not a product.
• Option (d): No reaction will occur: This is incorrect, as zinc, being an amphoteric metal, readily reacts with strong bases like NaOH.

Step 4: Conclusion.
The reaction between NaOH and Zn produces sodium zincate and hydrogen gas.
Conclusion:

Sodium Zincate and Hydrogen gas