Overall redox equation for acidified KMnO4 and ammonium iron(II) sulfate

[danago]

Homework Statement

Excess acidified potassium permanganate is added dropwise to an ammonium iron(II) sulfate solution. Write an overall redox equation for this process.

2. The attempt at a solution
Well I am not really sure what to do. I don't know what products are being formed. What should i do in a situation like this?

 

[Stevedye56]

Start with a balanced equation. Were you given the rules to follow for a redox reaction?

 

[Gokul43201]

What is the one thing that you neeed to know about potassium permanganate?

 

[danago]

How do i write a balanaced equation though? I don't know what the products are

 

[danago]

What is the one thing that you neeed to know about potassium permanganate?

Its soluble in water?

 

[Gokul43201]

Lots of things are soluble in water.

I quote from the first paragraph of the wiki on potassium permanganate:

Potassium permanganate is the chemical compound KMnO4. In this salt, manganese is in the +7 oxidation state. The salt is also known as "permanganate of potash" and "Condy's crystals". The permanganate ion is a strong oxidizing agent. It dissolves in water to give deep purple solutions, evaporation of which gives prismatic purple-black glistening crystals. It has a sweet taste and is odourless.

 

[danago]

Ok, so its an oxidising agent, and therefore, itself reduced. I think this is the correct equation for its reduction:

$$MnO_4 ^ - _{(aq)} + 8H^ + _{(aq)} + 5e^ - \to Mn^{2 + } _{(aq)} + 4H_2 O_{(l)}$$

Would i just combine that with the half equation of iron (II) being oxidised to iron (III) ions?

 

[Gokul43201]

Yup, you got it!

 

[danago]

Ahh ok. Thanks :)