Question

Hi, I need help with calculating the concentration of a potassium permanganate solution:

100 ml H2O + 5g KMnO4.

How do I do this? What information do I need in order to do so?
It was for a redox titration, by the way.

Answer 1

@RANE @Nnesha @Kainui @One098 No one else is online for me and sorry if you don't like this tagging stuff. I really need to get this done :/

Answer 2

Thank you. I'm stuck :l

Answer 3

Aright, here goes: @Preetha :)

Answer 4

I guess I'm suppose to use \[M _{1}V _{1}=M _{2} V _{2}\] since it was dilution. But I have no idea what V2 is. From the titration, the students that did the experiment provided the table

Answer 5

Pardon the horrible table, lol. That was all.

Answer 6

ohhh I see. Thanks anyways. Preetha didn't show up so i'll wait for other persons to come onine

Answer 7

:) Thanks.

Answer 8

@ganeshie8

Answer 9

Concentration is usually found in molarity which is moles of solute/Liter of solution.

Answer 10

You are given grams of solute, so you can convert that to moles using the molar mass.

Answer 11

And the volume of solution is essentially the volume of the water.

Answer 12

Make sense, @kym02?

Answer 13

It does :) Is the volume of the water for V1 or V2?

Answer 14

Since this is just making a solution from a solid I wouldn't use the dilution formula. I would use
\[M = \frac{ mol }{ L }\]

Answer 15

ohhh I see. okay, so i'll get the concentration of KMnO4 by that formula but since this is redox titration, how do i determine the concentration of FeSO4 ? I've been given the following:
40ml H2SO4 + x g FeSO4 and the titration table I provided earlier.

Answer 16

I'm having trouble interpreting the chart since there are no units. Do you have any more info?

Answer 17

It's in cm3. It's the same table for the other 2 redox titrations only thing, different readings.

Answer 18

cm^3 of what?

Answer 19

Volume of KMnO4 in the burette.

Answer 20

Oh, ok. Cool. So, what redox reaction are we dealing with?

Answer 21

Is there anyway that you could post the whole question/lab so that I can get some context to this problem?

Answer 22

Alright.
Redox Titration 1:Potassium Permanganate and Iron sulphate.
(I already provided the table for this)

Concentration of KMnO4----> 100ml water + 5g potassium permanganate.
Concentration of FeSO4-----> 40 ml Sulphuric acid + xg Iron sulphate.
In the burette was the KMnO4 and in the conical flask was 10ml of the solution of (FeSO4 + H2SO4)

That's it.

Answer 23

oh wait, that's not conc. for FeSO4. oops!

Answer 24

I have to determine the conc of FeSO4 using my titration results.

Answer 25

This is fairly long problem. Here is some really good info on the subject.
http://chemwiki.ucdavis.edu/Analytical_Chemistry/Analytical_Chemistry_2.0/09_Titrimetric_Methods/9D%3A_Redox_Titrations

Answer 26

ohhh thank you. By the way, one thing I don't understand is the purpose of the H2SO4. Why was that used?

Answer 27

That acts as a catalyst. It is not included in the overall reaction. :)

Answer 28

And you are very welcome! :D

Answer 29

Thank you. That clear things up! XD

Answer 30

No worries. :)