Question

Identify the products formed when zinc reacts with sodium hydroxide solution. Options:

• A. \( {Na}_2{ZnO}_2 + H_2O \)
• B. \( {Na}_2{ZnO}_2 + H_2 \)
• C. \( {Na}_3{ZnO}_3 + H_2O \)
• D. \( {Na}_3{ZnO}_3 + H_2 \)

Hint:

Zinc is amphoteric, meaning it reacts with both acids and bases. When reacting with bases like NaOH, it forms a soluble complex (sodium zincate) and releases hydrogen gas.

Answer 1

The Correct Option is B

Step 1: Understanding the reaction between zinc and sodium hydroxide

Zinc is an amphoteric metal, meaning it reacts with both acids and bases. When zinc reacts with a strong base like sodium hydroxide (NaOH), it dissolves, forming sodium zincate (\( \text{Na}_2\text{ZnO}_2 \)) and hydrogen gas (\( \text{H}_2 \)).

Step 2: Writing the balanced chemical equation

The reaction proceeds as:

\[ \text{Zn} + 2\text{NaOH} + 2\text{H}_2\text{O} \rightarrow \text{Na}_2\text{ZnO}_2 + \text{H}_2 \]

This shows that sodium zincate and hydrogen gas are the products of the reaction.

Step 3: Explanation of the reaction mechanism

Zinc initially reacts with hydroxide ions (\( \text{OH}^- \)) from sodium hydroxide. This forms a complex ion \( \text{Zn(OH)}_4^{2-} \) in aqueous solution.

The sodium ions (\( \text{Na}^+ \)) associate with the zincate ion to form sodium zincate \( \text{Na}_2\text{ZnO}_2 \).

Simultaneously, hydrogen gas (\( \text{H}_2 \)) is released.

Step 4: Verifying the correct option

Among the given options, only option (2) correctly represents the formation of sodium zincate (\( \text{Na}_2\text{ZnO}_2 \)) along with hydrogen gas (\( \text{H}_2 \)), making it the right choice.

Quick tip: Zinc’s amphoteric nature allows it to react with both acids and bases to form different products, like zincate when reacting with bases.

Answer 2

To solve the problem, we need to determine the products formed when zinc reacts with sodium hydroxide solution.

1. Understanding the Reaction:
When zinc reacts with sodium hydroxide (\( \text{NaOH} \)), the reaction produces sodium zincate (\( \text{Na}_2\text{ZnO}_2 \)) and hydrogen gas (\( H_2 \)) as the products. The reaction can be written as:

\[ \text{Zn} + 2 \text{NaOH} \rightarrow \text{Na}_2\text{ZnO}_2 + \text{H}_2 \] This is a typical reaction of zinc with an alkaline solution, producing hydrogen gas and sodium zincate. The reaction occurs in basic conditions, and the products are sodium zincate (\( \text{Na}_2\text{ZnO}_2 \)) and hydrogen gas (\( H_2 \)).

2. Conclusion:
Based on the given reaction and products, the correct answer is:

Final Answer:
The correct option is (B) \( \text{Na}_2\text{ZnO}_2 + H_2 \).