To estimate the amount of ferrous ammonium sulphate (FAS) dissolved in 1500 ml of the given unknown solution volumetrically.

**Estimation of
Ferrous Ammonium Sulphate (FAS)**

To
estimate the amount of ferrous ammonium sulphate (FAS) dissolved in 1500 ml of
the given unknown solution volumetrically. For this you are given with a
standard solution of ferrous sulphate ( FeSO_{4} )of normality 0.1024 N
and potassium permanganate solution as link solution.

**Oxidation : **5 Fe^{2}^{+}** **→** **5 Fe^{3+}** **+** **5e^{−}

**Reduction: **5Fe^{2}^{+}** **+** **MnO_{4}^{−}
+ 8H^{+} → 5Fe^{3+} + Mn^{2+} + 4H_{2}O

**Overall reaction: **5Fe^{2}^{+}** **+** **MnO_{4}^{−}
+ 8H^{+} → 5Fe^{3+} + Mn^{2+} + 4H_{2}O

**Short procedure: **

(Link
KMnO_{4})Vs **(**Standard FeSO_{4}
)

Burette
is washed with water, rinsed with KMnO_{4} solution and filled with
same solution up to the zero mark. Exactly 20 ml of standard FeSO_{4}
solution is pipetted out into the clean, washed conical flask. To this
solution, approximately 20ml of 2N sulphuric acid is added. This mixture is
titrated against KMnO_{4} Link solution from the burette. KMnO_{4}
is added drop wise till the appearance of permanent pale pink colour. Burette
reading are noted, the same procedure is repeated to get concordant values.

(Link
KMnO_{4})Vs **(**Standard FeSO_{4}
)

Volume of
KMnO_{4} (link) solution V_{1
}= ml

Normality
KMnO_{4} (link) solution N_{1} = ?N

Volume of
standard FeSO_{4} solution V_{2} = 20
ml

Normality
of standard FeSO_{4} solution N_{2} = 0.1024
N

According
to normality equation: V_{1}× N_{1} = V_{2} × N_{2}

N_{1}
= V_{2} × N_{2} / V_{1}

Normality
of KMnO_{4} (link) solution (N_{1}) = ----------X--------- N

**(**Unknown FAS) Vs (Link** **KMnO_{4}** **)

Burette
is washed with water, rinsed with KMnO_{4} solution and filled with
same KMnO_{4} solution up to the zero mark. Exactly 20 ml of unknown
FAS solution is pipetted out into the clean, washed conical flask. To this FAS
solution approximately 20ml of 2N sulphuric acid is added. This mixture is
titrated against KMnO_{4} Link solution from the burette. KMnO_{4}
is added drop wise till the appearance of permanent pale pink colour. Burette
reading is noted and the same procedure is repeated to get concordant values.

(Link
KMnO_{4})Vs **(**Unknown FAS)

Volume of
Unknown FAS solution V_{1 } =
20ml

Normality
of Unknown FAS solution N_{1 }= N

Volume of
KMnO_{4 }(link) solution V_{2 }= ml

Normality
KMnO_{4 }(link) solution

According
to normality equation: V_{1}× N_{1} = V_{2} ×

N_{2}
N_{1} = V_{2} × N_{2} / V_{1}

N_{1}=
------------------------ N

The
normality of unknown FAS solution =
--------Y---N

The
amount of FAS dissolved in 1 lit of the solution = (Normality) x (equivalent
weight)

The amount
of FAS dissolved in 1500 ml of the solution = Normality × equivalentweight × 1500 / 1000

= Y × 392 × 1500 /
1000

= g

The
amount of FAS dissolved in 1500 ml of the solution = g

Tags : Volumetric Analysis | Chemistry Practical Laboratory Experiment Volumetric Analysis | Chemistry Practical Laboratory Experiment

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