Question

A piece of magnesium is placed in a aqueous solution of cadmium nitrate, Cd(NO3)2(aq).
*Cd always forms a +2 ion

Is this the correct equation? How do I balance the charges?

Mg(s) + Cd(NO3)2(aq) -->Cd +2(aq) + Mg(NO3)2(aq)

Answer 1

@phi or @aaronq any help guys?

Answer 2

@Compassionate?

Answer 3

@shrutipande9 ?

Answer 4

do you have to balance this use redox reactions?

Answer 5

using*

Answer 6

well the question also asks for half reactions, but I think its already balanced

Answer 7

Okay, so they are redox reactions. Cadmium would be reduced on the other side.
Do you know how to assign oxidation numbers/states?

Answer 8

yep Mg is zero and goes two +2

Answer 9

and Cadmium goes from +2 to 0?

Answer 10

yeah thats right. can you write that in forms of equations?

Answer 11

including the electrons

Answer 12

Mg --> Mg +2 + 2e-
Cd +2 + 2e- --> Cd

Answer 13

but my concern is with the fact that Cd forms +2 ions in solution...

Answer 14

if it's forming a 2+ ion in solution, then it must be oxidized by something else. Perhaps water?

Answer 15

hmm yeah, I was just confused why the teacher emphasized that Cd forms +2 ions. So are you saying Cd would normally precipitate as a solid?

Answer 16

Ah I think you're right, it should be Cd (s) on the right, I think I just over-interpreted...

Answer 17

we'll the Cadmium forms 2+ ions because it's stable with that electronic configuration \((d^{10})\). Yeah, i think you're over thinking it. It should be reduced by magnesium in the reaction and be elemental (oxidation state of zero).

Answer 18

Thanks @aaronq! :) way to shine some light

Answer 19

no problem, dude !

Answer 20

:)