Question

Which of the following metals or nonmetals
are expected to displace Mn or Cl (respectively) from MnCl2?
1. Ca should displace Mn.
2. Br should displace Cl.
3. Cu should displace Mn.
4. I should displace Cl.

Answer 1

You want to look up the activity series. Here is a link.
http://en.wikipedia.org/wiki/Reactivity_series

This is a two part question.
To determine part A, which metal (Ca or Cu) will displace Mn^2+ from solution? Here is the answer. Any metal ABOVE the Mn in the table will displace the Mn^2+. Ca is above so it will. Cu is below so it will not.

For part B, the oxidizing power of the halogens goes like this.
F>Cl>Br>I
So Br will not displace Cl(Cl will displace Br but not the other way).

I will not displace Cl (Cl will displace I but not the other way)

Answer 2

Na will replace Mn