Gelatin added during the polarographic measurement carried out using dropping mercury electrode:a)Reduces streaming motion of Hg dropb)Decreases viscosity of the solutionc)Eliminates migrating currentd)Prevents oxidation of HgCorrect answer is option 'A'. Can you explain this answer?

Question

Answer

Gelatin  is  added  to  the  polarographic  measurement  to reduce  the  streaming  motion  of falling mercury drops

Answer

When one drop fall, it exert some effect on the second drop and size of mercury droplets may not be uniform.For accurate measurements uniform size of mercury droplets are required , gelatin help to attain a uniform size.

Answer

Gelatin added during the polarographic measurement carried out using dropping mercury electrode:

Introduction:
Polarography is an electrochemical technique used for the quantitative analysis of substances. It involves the measurement of currents produced during the reduction or oxidation of analytes at an electrode. The dropping mercury electrode (DME) is commonly used in polarographic measurements due to its stability and reproducibility.

Gelatin:
Gelatin is a protein derived from collagen, commonly obtained from animal sources like bones and skin. It is widely used in various industries, including food, pharmaceuticals, and analytical chemistry. In polarographic measurements, gelatin is added to the solution to modify certain properties and improve the accuracy of the measurement.

Reduces streaming motion of Hg drop:
When a mercury drop is used as the working electrode in polarography, it tends to exhibit streaming motion due to convection currents in the solution. This streaming motion can lead to instability and fluctuation in the measured current. By adding gelatin to the solution, the streaming motion of the mercury drop is effectively reduced. Gelatin acts as a viscosity modifier, increasing the viscosity of the solution, which in turn reduces the convection currents and stabilizes the drop.

Decreases viscosity of the solution:
The statement mentioned in the question is incorrect. Gelatin actually increases the viscosity of the solution, as explained in the previous point. It does not decrease the viscosity.

Eliminates migrating current:
Migrating current refers to the current that arises due to the migration of ions in the solution towards the working electrode. This can interfere with the accurate measurement of the analyte's current. Gelatin, being a macromolecule, can effectively trap and immobilize the migrating ions, thereby eliminating or reducing the migrating current. This allows for more precise measurements of the analyte's current.

Prevents oxidation of Hg:
Mercury is prone to oxidation when exposed to certain substances or conditions, leading to the formation of mercury oxide. This oxidation can interfere with the polarographic measurement by altering the behavior of the mercury drop. Gelatin acts as a protective layer on the mercury surface, preventing its oxidation and maintaining the stability of the drop. Therefore, gelatin prevents the oxidation of mercury during the polarographic measurement.

Conclusion:
In conclusion, gelatin added during the polarographic measurement carried out using a dropping mercury electrode primarily reduces the streaming motion of the mercury drop and eliminates migrating current. It also acts as a protective layer to prevent the oxidation of mercury. However, it does not decrease the viscosity of the solution; instead, it increases it.

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