Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
JEE Main2013ChemistryElectrochemistryActual

The Gibbs energy for the decomposition of Al ₂ O ₃ at 500 ~C is as follows : 2 3 Al ₂ O ₃ 4 3 Al + O ₂, _r G=+940 ~kJ ~mol ⁻¹ The potential difference needed for the electrolytic reduction of aluminium oxide at 500^ C should be at least :

Options

  1. A4.5 ~V
  2. B3.0 ~V
  3. C5.0 ~V
  4. D2.5 ~V

Correct answer

B. 3.0 ~V

Step-by-step solution

In the reaction 2 3 Al ₂ O ₃ 4 3 Al + O ₂ For the oxidation half-reaction Al ³⁺+3 e ⁻ Al no. of electron transfered (n)=3 aligned & G ^ =-n FE ^ & 940=3 96500 E ^ aligned aligned E ^ & = 940 10^3 ~J 3 96500 & =3.24 3 ~V aligned

Practice Electrochemistry on Quantrex Academy →

More from Electrochemistry

At 300 K, the molar conductivities of the aqueous solutions of three salts at two different concentrations are given below: Salt Concentration (M) Molar conductivity (S cm ^2 mol ⁻ 2026Given at 298 K: E^ _ Fe²⁺/Fe = X Volt; E^ _ Fe³⁺/Fe = Y Volt. The E^ _ Fe³⁺/Fe²⁺ in Volt at 298 K is given by: 2026For a general redox reaction Anode : Red ₁ Ox ₁^ n₁^+ + n₁ e^- Cathode : Ox ₂ + n₂ e^- Red ₂^ n₂^- Which of the following statements is incorrect? 2026Consider the following data. Electrolyte ^ _m (S cm ^2 mol ⁻¹ ) BaCl ₂ x₁ H ₂ SO ₄ x₂ HCl x₃ BaSO ₄ is sparingly soluble in water. If the conductivity of the saturated BaSO ₄ solut 2026One half cell in a voltaic cell is constructed by dipping silver rod in AgNO₃ solution of unknown concentration, other half cell is Zn rod dipped in 1 molar solution of ZnSO₄ . A v 2026At 298 K , the molar conductivity of x % (w/w) MX solution (aqueous) is 123.5 S cm ^2 mol ⁻¹ . The conductance of same solution is 1.9 10⁻³ S . The value of x is _______ 10⁻² . (Gi 2026An electrochemical cell, consist of the following two redox couples, M^ x+ (aq)/M(s)[E_ red ^ =+0.15 V ] and Fe³⁺(aq)/Fe(s)[E_ red ^ =-0.036 V ] . The cell EMF (E_ cell ) is record 2026Consider the following two half-cell reactions along with the standard reduction potential given: CO₂ + 6H^+ + 6e^- CH₃ OH + H₂ O E°_ red = 0.02 V 1 2 O₂ + 2H^+ + 2e^- H₂ O E°_ red 2026 Full Electrochemistry list All JEE Main PYQs