Question

The mental that produces H₂ with both dil HC/ and NaOH (aq) is

• A. Fe
• B. Zn
• C. Mg
• D. Ca

Answer 1

The Correct Option is B

To determine which metal produces hydrogen gas (H\(_2\)) with both dil. HCl and NaOH(aq), let's analyze the reactivity of different metals with these reagents.
1. With dilute HCl: The metal must react with hydrochloric acid (HCl) to produce hydrogen gas. For example: \[ \text{Zn} + 2\text{HCl} \rightarrow \text{ZnCl}_2 + \text{H}_2(g) \] Zinc (Zn) reacts with dilute hydrochloric acid to produce hydrogen gas.
2. With NaOH(aq): The metal must also react with aqueous sodium hydroxide (NaOH) to produce hydrogen gas. This occurs with metals like zinc: \[ \text{Zn} + 2\text{NaOH} \rightarrow \text{Na}_2\text{ZnO}_2 + \text{H}_2(g) \] Zinc reacts with sodium hydroxide to form hydrogen gas. Thus, zinc (Zn) is the only metal that reacts with both dilute HCl and NaOH(aq) to produce hydrogen gas. Thus, the correct answer is \(Zn\).

The correct option is(B): \(Zn\)

Answer 2

When metals react with dilute acids like hydrochloric acid (HCl), they produce hydrogen gas (\( H_2 \)) through a displacement reaction. Similarly, some metals also react with bases like sodium hydroxide (NaOH) to release hydrogen gas. Among the metals:

• Fe (Iron) reacts with dilute HCl to produce hydrogen gas, but it does not react with NaOH.
• Zn (Zinc) reacts with both dilute HCl and NaOH to produce hydrogen gas. Zinc reacts with dilute HCl to form ZnCl\(_2\) and hydrogen gas, and it also reacts with NaOH to form sodium zincate (Na\(_2\)ZnO\(_2\)) and hydrogen gas.
• Mg (Magnesium) reacts with both dilute HCl and NaOH, but it's more reactive and doesn't fit the common pattern compared to zinc.
• Ca (Calcium) reacts with water to produce hydrogen, but it doesn't readily react with NaOH.

Thus, the correct answer is \({(B)} \), as zinc is the metal that reacts with both dilute hydrochloric acid and sodium hydroxide to release hydrogen gas.