Question

Which of the following ions does not liberate hydrogen gas on reaction with dilute acids ?

Answer 1

`Mn^(2+)` does not liberate hydrogen gas on reaction with dilute acids

Explanation:

These are transition metals and reactivity decreases as we move from `Ti^(2+)` to `V^(2+)` to `Cr^(2+)` and finally `Mn^(2+)` in the fourth row of periodic table. As such `Mn^(2+)` does not liberate hydrogen gas on reaction with dilute acids.