Question

The quantity of Mohrs salt required to prepare 0.05M 100ml solution is
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Answer 1

Answer:

Hey !!

Chemical equation

Molecular equations

2 KMnO₄ + 3 H₂SO₄ ------> K₂SO₄ + 3 H₂O + 5[O]

2 FeSO₄ (NH₄)₂SO₄.6H₂O + H₂SO₄ + [O] ----> Fe₂(SO₄)₂ + 2(NH₄)₂SO₄ + 13H₂O] × 5

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2 KMnO₄ + 8H₂SO₄ + 10FeSO₄.SO₄.6H₂O ----->

K₂SO₄ + 2MnSO₄ + 5Fe₂(SO₄)₃ + 10(NH₄)₂ SO₄ + 68H₂O

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IONIC EQUATIONS

MnO₄⁻ + 8H⁺ + 5e¹ ------> Mn²⁺ + 4H₂O

Fe²⁺ -------> Fe³⁺ + e⁻¹] × 5

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MnO₄⁻ + 8H⁺ + Fe²⁺ --------> Fe³⁺ + Mn²⁺ + 4H₂O

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Indicator

KMnO₄ is a self-indicator

End Point

Colourless to permanent pink colour (KMnO₄ in burette)

Procedure

Prepare 250 ml of M/20 Mohr's salt solution by dissolving 4.9 g of Mohr's salt in water. Rinse the pipette with the M/20 Mohr's salt solution and pipette out 20.0 ml of it in a washed titration flask.

Rinse and fill the burette with the given KMnO₄ solution.

Add one test-tube ( 20 ml ) full of dilute sulphuric acid ( 2 M ) to the solution in titration flask.

Note the initial reading of the burette.

Now add KMnO₄ solution from the burette till a permanent light pink colour is imparted to the solution in the titration flask on addition of last single drop of KMnO₄ solution.

Note the final reading of the burette.

Repeat the above steps 4-5 times to get a set of three concordant readings.

Observation

Weight of watch glass = 50.498 g

Weight of watch glass + Mohr's salt = 4.9 g

Weight of Mohr's salt = 4.90 g

Volume of Mohr's salt solution prepared = 250 ml

Molarity of Mohr's salt solution = M/20

Volume of Mohr's salt solution taken for each titration = 20.0 ml

S.No = 1

Initial reading of the burette = 2.00 ml

Final reading of the burette = 19.50 ml

S.No = 2

Initial reading of the burette = 2.14

Final reading of the burette = 19.45

S.No = 3

Initial reading of the burette = 2.25

Final reading of the burette = 19.67

S.No = 4

Initial reading of the burette = 2.91

Final reading of the burette = 20.1

NOTE :- I have performed this experiment so according to that i have given the values.

Concordant volume = x ml

Calculations

(a) Molarity of the KMnO₄ solution

From the overall balanced chemical equation, it is clear that 2 moles of KMnO₄ reacts with 10 moles of Mohr's salt

∴ MkMno₄ × VKMnO₄ / M mohr's salt × V Mohr's salt =

where,

M KMno₄ = Molarity of KMnO₄ solution

V KMnO₄ = Volume of KMnO₄ solution

M Mohr's salt = Molarity of Mohr's salt solution

V Mohr's salt = Volume of Mohr's salt solution

M KMnO₄ × x / 1 / 20 × 20 = 2/10

M KMnO₄ = 2/10 × 1/x = 2/10 x

(b) Strength of the KMnO₄ solution

Molar mass of KMnO₄ = 158 g mol⁻¹

Strength (in g/L) = Molarity × Molar mass = 2/10x × 158 gL⁻¹

GOOD LUCK !!

Step-by-step explanation: