Question

Which of the following has least tendency to liberate H$_2$ from mineral acids?

• A. Cu
• B. Mn
• C. Ni
• D. Zn

Hint:

Metals below hydrogen in the reactivity series do not react with acids to produce H$_2$ gas.

Answer 1

The Correct Option is A

Step 1: Understanding Reactivity Series
The tendency of a metal to liberate hydrogen from acids depends on its position in the electrochemical series.
More electropositive metals react with acids to release H$_2$ gas.
Step 2: Analyzing the Given Metals
Zn and Mn are highly reactive and readily react with acids.
Ni has moderate reactivity.
Cu lies below hydrogen in the reactivity series, meaning it does not react with acids to liberate H$_2$.
Final Answer: Copper (Cu) has the least tendency to liberate H$_2$ from acids.

Answer 2

The element with the least tendency to liberate H₂ from mineral acids is Copper (Cu):

Copper is a noble metal with low chemical reactivity compared to other metals like zinc, iron, or magnesium.

It does not easily react with dilute mineral acids such as hydrochloric acid or sulfuric acid to produce hydrogen gas.

This is because copper lies below hydrogen in the reactivity series, meaning it cannot displace hydrogen ions from acids to release H₂ gas.

In contrast, more reactive metals readily liberate hydrogen by reacting with acids.

Therefore, among common metals, Cu shows the least tendency to evolve hydrogen from mineral acids.