Question

Iron in the 2 oxidation state reacts with potassium dichromate to produce Fe3 and Cr3 according to the equation: 6 Fe2 (aq) Cr2O72-(aq) 14 H (aq) <----> 6 Fe3 (aq) 2 Cr3 (aq) 7 H2O(l) How many milliliters of 0.2937 M K2Cr2O7 are required to titrate 132.0 mL of 0.1782 M Fe2 solution

Answer 1

Given :

Volume of
`Fe^(2+)` , V = 132 mL .

Molarity of
`Fe^(2+)`, M = 0.1782 M .

To Find :

How many milliliters of 0.2937 M
`K_2Cr_2O_7` are required to titrate 132.0 mL of 0.1782 M
`Fe^(2+)` solution .

Solution :

Moles of
`Fe_2` :

`n=0.1782* (132)/(1000)\ mol\\\\n=0.264\ mol`

Now , 1 mole of
`K_2Cr_2O_7` reacts with 6 mole of
`Fe^(2+)` .

So , moles of
`K_2Cr_2O_7` required is :

`N=(0.264)/(6)=0.044\ mol`

Volume required is :

`V=(N)/(M)\\\\V=(0.044)/(0.2937)\ L\\\\V=0.15\ L=150\ mL`

Hence , this is the required solution .