oxidized or reduced

Leslie Romo 1C
Posts: 21
Joined: Fri Sep 25, 2015 3:00 am

oxidized or reduced

This is probably a really simple question but I'm still confused and need some clarification...

an electrode is oxidized and loses e-
an cathode is reduced and gains e-
is this correct????

Also in this equation...:
how would you know what is being oxidized or reduced...?

2AS (s) +3 CL2(g) ---> 2ASCL3

MaxHuang Section 1B
Posts: 11
Joined: Fri Sep 25, 2015 3:00 am

Re: oxidized or reduced

Hi!
An anode is actually the left side of the battery (conventionally) that is getting oxidized and loses the electron.
The cathode is the right side of the battery that is getting reduced and gains the electron.

In that equation, we know that the Cl has a minus charge associated with it. So Cl2 would be a 2-. As (s) will have a charge of 0. So on the left side of the equation we will have a total charge of 6- since we have 3 moles of Cl2 and the As (s) does not affect the charge. On the right hand side, we will need a charge of 6- to balance the charges in our equation. Thus, we know that the right hand side needs a charge of 6-. We have 2 moles of AsCl3. Thus, one mol of AsCl3 will have to have a charge of 3-. Since Cl has a charge of -1, and we have Cl3, our AsCl3 becomes a charge of -3 with As not affecting the charge. So, since the Cl and the As didn't change charges from the left hand side to the right hand side, there was no oxidation or reduction in this reaction.