Question

A 6M H₂SO₄ solution will be used in preparing the sodium oxalate solution for titration in this experiment.

a) Using your 100 mL graduated cylinder (and a piece of parafilm to cover the mouth of the graduated cylider),
briefly explain, and show your calculations, how you will prepare 200 mL of 1 M H₂SO₄ for this purpose. (1 pt.)

b) What is the role of H₂SO₄ in the RedOx reaction? (0.5 pt.)

Answer 1

a) We are supposed to use 6M H2SO4 in the experiment. It means in order to prepare 200 mL of 1M H2SO4 we have to use 6M H2SO4 and dilute it.

Our aim is to find volume of 6M H2SO4 to be taken to dilute.

Initially for stock: M1 = 6 M 7 V1 = ?

Finally, M2 = 1M V2 = 200 mL.

By Law of dilution,

M1 x V1 = M2 x V2

6 x V1 = 1 x 200

V1 = 200 / 6

V1 = 33.33 mL

Preparation : 33.33 mL of 6M H2SO4 is taken in 200 mL volumetric flask and diluted to 200 mL with distilled water .

This gives a 200 mL 1M H2SO4 solution.

b) Role of H2SO4 in Redox titration:

In certain redox reaction like one we are talking about requires strong Acidic medium. Only under acidic conditions these conversions are possible.

E.g. Here in Oxalic acid & KMnO4 titration,

Mn(VII) Mn(II) this conversion occurs only under acidic conditions.

MnO₄⁻ (aq) + 8H⁺ (aq) + 5e⁻ Mn²⁺ (aq) + 4H₂O

Hence the importance of conc. H₂SO₄ in Redox titration.

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