An acidic solution contains a lot of H
+ and minimal of OH
-, right? Let's think what happens when you have these cations in water. The equation, essentially, would follow;
H
2O + M
n M(OH)
n + H
+or
H
+ + OH
- + M
n M(OH)
n + H
+where M is representative for the listed cations and n is their charge number, respectively. Co
+2 would form Co(OH)
2 and Fe
+3 would form Fe(OH)
3, the cobalt leaving 2H
+ and the iron leaving 3H
+.