Question

which of the following metals fails to evolve H2 gas on reacting with dilute HCl​

Answer 1

Question :

which of the following metals fails to evolve H2 gas on reacting with dilute HCl​?

a)Zn

b) Al

c) Cu

d) Mg

Answer:

copper

Explanation:

Only that metals can liberate Hydrogen from acid which are more reactive than hydrogen.. And reduction potential is a good method to look on reactivity. More is red pot less ll be reactivity.

Now Red pot of hydrogen is 0,  so that metals can liberate hydrogen which has - ve red pot.

Here o only Cu has +ve red pot.. So it cant liberate H2.

hope this is helpful

try to keep full question if options were there keep that even

Answer 2

Answer:

copper

Explanation:

The answer of such questions is based on electrochemical series.

Here one way to think is

Cu is below hydrogen in electrochemical series where as other metals are above the hydrogen hence they can reduce hydrogen ion present in acid to hydrogen gas.

This electrochemical series is available in NCERT class 12th chemistry part I textbook.

Hope it will help