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Chemistry - Electrochemistry Question with Solution | TestHub

ChemistryElectrochemistryGalvanic cells/Nernst Equation/Concentration CellsMedium2 minQB

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Passage / Comprehension

The cavities in teeth are often filled with an alloy of metals to avoid bacterial infections. However, when a person with a dental filling accidentally chews an active metal like aluminium foil, they experience severe pain in their teeth. The pain is due to a spontaneous discharge of a galvanic cell reaction that is set up inside the person's mouth. The active metal serves as the anode, and the dental filling acts as an inert electrode on which the reduction of O₂ gas takes place.

$E_{\frac{A l ^{3 +}}{A l}}^{o} = 1.66 v o lt; E_{O_{2}, \frac{H ^{+}}{H _{2} O}}^{0} = + 1.23 v o lt$

What is the net cell reaction assuming acidic conditions in the mouth ?

Options:

Answer:

Solution:

Anode: $Al ⟶ Al^{3 +} + 3 e$

Cathode: $O_{2} + 4 H^{+} + 4 e^{-} \to 2 H_{2} O$

Net cell reaction:

$4 Al + 3 O_{2} + 12 H^{+} \to 4 Al^{3 +} + 6 H_{2} O$

Stream:JEESubject:ChemistryTopic:ElectrochemistrySubtopic:Galvanic cells/Nernst Equation/Concentration Cells

⏱ 2mℹ️ Source: QB

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