Question

What is the concentration of Cr2O7 in mol/L?

The potassium dichromate solution is first standardized by titration with 20.00 mL of an acidified 0.06 mol/L solution of the primary standard, iron(II) ammonium sulfate-6-water. The standardized dichromate solution is then titrated against a sample of the acidified tin(II) chloride solution.

TITRATION OF IRON(lI) SOLUTION

(volume of K2Cr2O7(aq) required to react with 20.00 ml of 0.06 mol/L Fe2+(aq))

Trial; ( 1 ) { 2 } [ 3 ] | 4|
Final vol: (13.8) {24.4} [35.2] |45.9|
Initial vol: (2.3) {13.8 } [24.4 ] |35.2|

(that is the titration table)

Answer 1

Well, we can give you the redox equations, and establish the stoichiometric equivalence..

Explanation:

The iron(II) salt is OXIDIZED....

`Fe^(2+) rarr Fe^(3+) +e^(-)`

Dichromate ion, `Cr(VI+)`, is REDUCED to `Cr^(3+)`..

`Cr_2O_7^(2-)+14H^+ + 6e^(-) rarr 2Cr^(3+) + 7H_2O`

And overall...

`Cr_2O_7^(2-)+6Fe^(3+) rarr 6Fe^(2+) + 2Cr^(3+) + 7H_2O`

The standardized dichromate solution is then reacted with stannous ion...

`Sn^(2+) rarr Sn^(4+) + 2e^(-)`

Anyway you have the data....