A solution contains Fe²⁺, Fe³⁺ and I^– ions. This solution was treated with iodine at 35°C. E° for Fe³⁺ / Fe²⁺ is + 0.77 V and E° for I₂/2I^– = 0.536 V. The favourable redox reaction is:

I₂ will be reduced to I^-
There will be no redox reaction
I^- will be oxidised to I₂
Fe²⁺ will be oxidised to Fe³⁺

Solution

If the E°cell for a given reaction has a negative value, then which of the following gives the correct relationships for the values of ΔG° and K_eq ?

ΔG° >0 ;K_eq > 1
ΔG° <0 ;K_eq > 1
ΔG° <0 ;K_eq < 1
ΔG° >0 ;K_eq < 1

Solution

Standard electrode potential for Sn⁴⁺ / Sn²⁺ couple is +0.15V and that for the Cr³⁺/ Cr couple is – 0.74 V. These two couples in their standard state are connected to make a cell. The cell potential will be :

+ 1.19 V
+0.89 V
+ 0.18 V
+1.83 V

Solution

The electrode potentials for Cu²⁺(aq) + e^– ⟶ Cu⁺(aq) and Cu⁺(aq) + e^– ⟶ Cu(s) are +0.15 V and + 0.50, respectively. The value of 2 E°_Cu²⁺/Cu will be :

0.500 V
0.325 V
0.650 V
0.150 V

Solution

Standard electrode potential of three metals X, Y and Z are– 1.2 V, +0.5 V and – 3.0 V,respectively.The reducing power of these metals will be :

Y > Z > X
X > Y > Z
Z > X > Y
X > Y > Z

Solution

Consider the following relations for emf of a electrochemical cell:
(i)emf of cell= (Oxidation potential of anode)–(Reduction potential of cathode)
(ii)emf of cell = (Oxidation potential of anode) +(Reduction potential of cathode)
(iii)emf of cell = (Reduction potential of anode) + (Reduction potential of cathode)
(iv)emf of cell = (Oxidation potential of anode) – (Oxidation potential of cathode)Which of the above relations are correct?

(ii) and (iv)
(iii) and (i)
(i) and (ii)
(iii) and (iv)

Solution

Option (ii) and (iv) are correct.

Solution

An increase in equivalent conductance of a strong electrolyte with dilution is mainly due to:

increase in ionic mobility of ions
100% ionisation of electrolyte at normal dilution
increase in both i.e. number of ions and ionic mobility of ions
increase in number of ions

Solution

Dilution of strong electrolytes increases ionisation,hence ionic mobility of ions which in turn increases equivalent conductance of the solution.

For the reduction of silver ions with copper metal, the standard cell potential was found to be + 0.46 V at 25°C.The value of standard Gibbs energy, ΔG° will be(F =96500 C mol^-1)

– 89.0 kJ
– 89.0 J
– 44.5 kJ
– 98.0 kJ

Solution

The equivalent conductance of \(\frac{M}{32}\) solution of a weak monobasic acid is 8.0 mho cm² and at infinite dilution is 400 mho cm². The dissociation constant of this acid is:

1.25 × 10^-6
6.25 × 10^-4
1.25 × 10^-4
1.25 × 10^-5

Solution

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