[xstrae]

Hi,

0.84g iron ore containing 'x' percent of iron was taken in a solution containing all the iron in ferrous condition. The solution required 'x' cc of a dichromatic solution for oxidizing the iron content to ferric state. Calculate the strength of the dichromatic solution.

Can someone please explain how to do this problem?

thanks

[Borek]

What about reaction equation?

[xstrae]

It wasnt mentioned.

anyway, this is what I think it must be: Fe²⁺ + Cr₂O₇ --> Fe³⁺ + Cr³⁺
how do i do this??

[Borek]

You have it described, it doesn't have to "mentioned".

Balance it.

http://www.chembuddy.com/?left=balancing-stoichiometry&right=balancing-redox

[xstrae]

6Fe²⁺ + Cr₂⁺⁶ --> 6Fe³⁺ + 2Cr³⁺

now what?
and you have given me that link about 5 times already. I have almost mugged it up unknowingly!

[Borek]

Now, as I understand the question, x is just a numerical value identical in both cases, but referring to different units. Setup an equation combining x% (hint: convert mass to moles) with x cc (hint: use second unknown, C_dichromate), solve for C_dichromate. If x cancels out, you have a numerical solution, If x doesn't cancle out, you have an equation for C_dichromate. In both cases question is solved.

and you have given me that link about 5 times already.

Start every time with balanced equation, you won't see the link again.

[xstrae]

ok I got Normality of dichromate solution as 0.15N. is it correct?
thanks for your help.

by the way what is the chemical formula of the monosodium salt of oxalic acid?

[Borek]

ok I got Normality of dichromate solution as 0.15N. is it correct?

No idea. Perhaps someone else will have a time to check.

by the way what is the chemical formula of the monosodium salt of oxalic acid?

Start with oxalic acid formula.

[xstrae]

oxalic acid - H₂C₂O₄
sodium - Na

Perhaps someone else will have a time to check.

Please dont bother answering questions if you dont have time to complete it.

[Alberto_Kravina]

oxalic acid - H2C2O4
sodium - Na

Yes - exactly - and in your case a hydrogen atom is substituted with a Na⁺ Ion

[xstrae]

allright thanks.

[Borek]

Perhaps someone else will have a time to check.

Please dont bother answering questions if you dont have time to complete it.

OK - next time you will even not get a hint from me.

[xstrae]

I didnt mean to be rude.. Maybe it was because I very badly wanted to learn to do the problem, it was just a bit irritating that you didnt care to check my answer. anyway, sorry on my part.

[Gerard]

Now, as I understand the question, x is just a numerical value identical in both cases, but referring to different units. Setup an equation combining x% (hint: convert mass to moles) with x cc (hint: use second unknown, Cdichromate), solve for Cdichromate. If x cancels out, you have a numerical solution, If x doesn't cancle out, you have an equation for Cdichromate. In both cases question is solved.

-Again the concept of dimensional analysis can be used here, if you have any problem with the chemistry question i suggest that you look at thier units first and try to find out how to cancell then out.. i suggest you read the book "Chemical Process Principles" by Felder for a thorough discussion on dimensional analysis...
and i would also like to suggest that please be humble in asking questions you see, try to solve the problem yourself first then post it here on how you solve it then let the prfessionals scan your solutions for mistakes...
remember if you wont try it yourself how will you learn, right?
thank you
keep it up
-artificial student