Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
JEE Main2015ChemistryElectrochemistryActual

At 298 K , the standard reduction potentials are 1 . 51 V for M n O 4 - | M n 2 + , 1 . 36 V for C l 2 | C l - , 1 . 07 V for B r 2 | B r - , 0 . 54 V for I 2 | I - . At pH = 3 , permanganate is expected to oxidize: R T F = 0.059

Options

  1. AC l - and B r -
  2. BB r - and I -
  3. CI - only
  4. DC l - , B r - and I -

Correct answer

B. B r - and I -

Step-by-step solution

M n O 4 - + 8 H + + 5 e - → M n 2 + + 4 H 2 O   E M n O 4 - M n 2 + = E o - 0.059 5 log ⁡ M n 2 + M n O 4 - H + 8 = 1.51 - 0.059 5 log ⁡ 1 10 - 3 8 (Assuming M n O 4 - = M n 2 + = 1 M ) = 1.51 - 0.059 5 × 24 = 1.51 - 0.28 = 1.23   V E r e d M n O 4 - M n 2 + o = 1.23   V > E r e d B r 2 B r - o > E r e d I 2 I - o   i.e. it will oxidise B r - and I - , only.

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