## How to determine anode and cathode in 6.57?

Tiffany Chao 2H
Posts: 117
Joined: Fri Aug 09, 2019 12:17 am

### How to determine anode and cathode in 6.57?

6.57: 6.57 Use the data in Appendix 2B and the fact that, for the half- reaction F2(g) + 2 H+ (aq) + 2 e- --> 2HF (aq), E* = + 3.03 V, to calculate the value of Ka for HF.

Based on F2 (g) + 2 e- --> 2F-, E*= +2.87V, how am I suppose to know which one is the cathode and anode?

Thanks

Posts: 103
Joined: Sat Aug 24, 2019 12:15 am

### Re: How to determine anode and cathode in 6.57?

this is the half-reaction for the cathode. We know this because there are electrons being added to the reactants, reducing the Fluorine.

JonathanS 1H
Posts: 101
Joined: Thu Jul 11, 2019 12:17 am

### Re: How to determine anode and cathode in 6.57?

Because you are given Eo for the whole reaction, we can use Eo = Ecathode - Eanode, all we need is the E value for the other half reaction and arrange the equation to give us the given Eo value.

Tiffany Chao 2H
Posts: 117
Joined: Fri Aug 09, 2019 12:17 am

### Re: How to determine anode and cathode in 6.57?

Adam Kramer 1A wrote:this is the half-reaction for the cathode. We know this because there are electrons being added to the reactants, reducing the Fluorine.

Sorry I meant F2 (g) + 2 e- --> 2F- is the cathode and F2(g) + 2 H+ (aq) + 2 e- --> 2HF (aq) is the anode according to the solutions manual. It says the E*cell = -0.16V
Last edited by Tiffany Chao 2H on Mon Mar 02, 2020 8:32 pm, edited 2 times in total.

Chris Charton 1B
Posts: 69
Joined: Mon Jun 17, 2019 7:23 am

### Re: How to determine anode and cathode in 6.57?

The cathode will be the reaction with the larger E* value.

Natalie Benitez 1E
Posts: 100
Joined: Fri Aug 02, 2019 12:15 am

### Re: How to determine anode and cathode in 6.57?

The cathode should be the one with the larger E value.

Emily Burghart 1k
Posts: 50
Joined: Wed Sep 18, 2019 12:17 am

### Re: How to determine anode and cathode in 6.57?

Natalie Benitez 1E wrote:The cathode should be the one with the larger E value.

Why again is the cathode the one with the larger E value?