# Chemsitry question

Watch
Announcements
Thread starter 7 months ago
#1
Can someone help me with this please?

Explain which species is reduced in the reaction between magnesium and iron chloride.
3 Mg + 2 FeCl3 ⟶ 2 Fe + 3 MgCl2
0
reply
7 months ago
#2
I would say the first thing to do is remember that reduction is gain of electrons. Iron is reduced because the charge on iron in FeCl3 is +3 and it gains electrons to form an overall charge of 0. I hope this helps
2
reply
7 months ago
#3
Iron has been reduced as its oxidation state has decreased from +3 to 0.
Last edited by Deggs_14; 7 months ago
1
reply
Thread starter 7 months ago
#4
(Original post by hilary08)
I would say the first thing to do is remember that reduction is gain of electrons. Iron is reduced because the charge on iron in FeCl3 is +3 and it gains electrons to form an overall charge of 0. I hope this helps
How do you know that the charge of iron in FeCl3 is +3?
0
reply
7 months ago
#5
(Original post by rsidofdhoidsh)
How do you know that the charge of iron in FeCl3 is +3?
Because your should know that chlorine has an oxidation state of -1 except if it’s combined with oxygen or a halogen higher than it in its group.
This is true for all halogens. (except fluorine, see @Deggs_14 below correcting my mistake)

Since you have 3 Cl with each having an oxidation state of -1 your total would come to -3.
And since the compound itself has no charge, you can assume that the oxidation number of the compound equals 0.

Therefore, Fe has to have an oxidation state of +3 as:

-3 + 3 = 0.

Hope this helps.
Last edited by Adambrl; 7 months ago
1
reply
7 months ago
#6
(Original post by rsidofdhoidsh)
How do you know that the charge of iron in FeCl3 is +3?
Because this is an ionic compound with three Cl- ions and one Fe 3+ ion. The oxidation states are the ionic charges.
0
reply
Thread starter 7 months ago
#7
(Original post by Adambrl)
Because your should know that chlorine has an oxidation state of -1 except if it’s combined with oxygen or a halogen higher than it in its group.
This is true for all halogens.

Since you have 3 Cl with each having an oxidation state of -1 your total would come to -3.
And since the compound itself has no charge, you can assume that the oxidation number of the compound equals 0.

Therefore, Fe has to have an oxidation state of +3 as:

-3 + 3 = 0.

Hope this helps.
Alright, I think I understand it now. Ty!
0
reply
Thread starter 7 months ago
#8
(Original post by Deggs_14)
Because this is an ionic compound with three Cl- ions and one Fe 3+ ion. The oxidation states are the ionic charges.
Ty
0
reply
7 months ago
#9
(Original post by Adambrl)
Because your should know that chlorine has an oxidation state of -1 except if it’s combined with oxygen or a halogen higher than it in its group.
This is true for all halogens.

Since you have 3 Cl with each having an oxidation state of -1 your total would come to -3.
And since the compound itself has no charge, you can assume that the oxidation number of the compound equals 0.

Therefore, Fe has to have an oxidation state of +3 as:

-3 + 3 = 0.

Hope this helps.
The oxidation state of fluroine is always -1, even in interhalogen compounds and when bonded covalently with other non-metals.
0
reply
Thread starter 7 months ago
#10
(Original post by Deggs_14)
The oxidation state of fluroine is always -1, even in interhalogen compounds and when bonded covalently with other non-metals.
chlorine*?
0
reply
7 months ago
#11
(Original post by rsidofdhoidsh)
chlorine*?
Referring to my wrongful claim that all halogens are -1 except when combined with Oxygen or a halogen higher than it in the group. Fluorine is an exception with it always being -1
0
reply
7 months ago
#12
(Original post by rsidofdhoidsh)
chlorine*?
Chlorine undergoes disproportionation with water or alkali under various conditions into positive oxidation states, like NaOCl used in bleaches and detergents.
0
reply
Thread starter 7 months ago
#13
(Original post by Adambrl)
Referring to my wrongful claim that all halogens are -1 except when combined with Oxygen or a halogen higher than it in the group. Fluorine is an exception with it always being -1
Ohh alrighty
0
reply
X

Write a reply...
Reply
new posts
Back
to top
Latest
My Feed

### Oops, nobody has postedin the last few hours.

Why not re-start the conversation?

see more

### See more of what you like onThe Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

### Poll

Join the discussion

#### Should there be a new university admissions system that ditches predicted grades?

No, I think predicted grades should still be used to make offers (581)
34.2%
Yes, I like the idea of applying to uni after I received my grades (PQA) (698)
41.08%
Yes, I like the idea of receiving offers only after I receive my grades (PQO) (342)
20.13%
I think there is a better option than the ones suggested (let us know in the thread!) (78)
4.59%

View All
Latest
My Feed

### Oops, nobody has postedin the last few hours.

Why not re-start the conversation?

### See more of what you like onThe Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.