Question

Which of the following reactions would be classified as oxidation-reduction?
Check all that apply.
2Na(s)+Cl2(g)→2NaCl(s)
Na(s)+CuCl(aq)→NaCl(aq)+Cu(s)
NaCN(aq)+CuCl(aq)→NaCl(aq)+CuCN(s)

Answer 1

what do you think?

Answer 2

i thought it was the first one and last one but i got it wrong...

Answer 3

let's look at this more closely

Answer 4

electrons have to be transferred from one element to the other, in the process of the reaction, so one is oxidized and the other is reduced.

Answer 5

how do you know Na doesnt have a charge?

Answer 6

@marmar10 interesting point, that might be where the point of confusion is.

For your reference: "Any pure element—even if it forms diatomic molecules like chlorine (Cl2)—has an oxidation state of zero. Examples of this are Cu or O2."

Na(s)+CuCl(aq)→NaCl(aq)+Cu(s)





Na goes from 0 to +1 so it's oxidized
Cu goes from +1 to 0 so it's reduced.

so electrons are lost from sodium
and electrons are gained from copper.