Electrochemistry & Conductance Test (19-12-2016) - IIT JAM MCQ

E₁, E₂ and E₃ are the e.m.f.s. of the following three galvanic cells respectively:

(i) Zn(s)/Zn²⁺ (0.1M) || Cu²⁺ (1M)/Cu(s).

(ii) Zn(s)/Zn²⁺ (1M) || Cu²⁺ (1M)/Cu(s).

(iii) Zn(s)/Zn²⁺ (1M) || Cu²⁺ (0.1M)/Cu(s).

Which one of the following is true?

The temperature coefficient of a galvanic cell is +5.0 × 10^–5 vk^–1. During the discharge of the cell, the cell temperature:

The cell reaction involving quinhydrone electrode is:

What will be the electrode potential at pH = 3:

The specific conductivity of a saturated solution of silver chloride is 2.30 × 10^–6 mho cm^–1 at 25°C. The solubility of silver chloride at 25°C if = 61.9 mho cm² mol^–1 and  = 76.3 mho cm² mol^–1:

The molar conductance at infinite dilution of aluminium sulphate is 858 ohm^-1 cm² mol^-1. Given the molar ionic conductance of sulphate ions as 160 ohm^-1 cm² mol^-1, the molar ionic conductance of Al³⁺ ion is:

Two students use same stock solution of ZnSO₄ and a solution of CuSO₄. The emf of one cell is 0.03 V higher than that of other. The concentration of CuSO₄ in the cell with higher emf value is 0.5 M. Find out the concentration of CuSO₄ in the other cell: 

During electrolysis of H₂SO_4(aq) with high charge density, H₂S₂O₈ formed as by product. In such electrolysis 22.4 L H_2(g) and 8.4 L O_2(g) liberated at 1 atm and 273 K at electrode. The moles of H₂S₂O₈ formed is:

Given

the formation constant of the complex Zn(NH₃)₄²⁺ is approximately:

What is the standard electrode potential for the electrode, MnO^–₄ /MnO₂ in an acid solution:

Calculate the liquid function potential at 25°C between two solutions of HCl having mean ionic activities of 0.01 and 0.001, respectively. The transference number of H⁺ ion (f_t) in HCl may be taken as 0.83.

Molar conductance is plotted agains C^1/2 (mol / lit^–1) for three electrolytes (NaCl, HCl, NH₄OH)

which of the following is correct?

Given the standard oxidation potentials,

it is easier to oxidise Fe²⁺ to Fe³⁺ in:

Identify in which of following condition working of cell takes place:

Ag | Ag⁺, KI || AgI | Ag emf is E, then K_sp of AgI is given as:

During the electrolysis of AgNO₃ (using Pt electrodes) concentration around cathode as well as anode falls from 4M to 3M. What will happen if this happened with Ag electrodes:         

We observe blue colour if:

Rusting on the surface of iron involves:      

   The ratio of  for Ca₃(PO₄)₂ will be equal to:

The amount of electricity which releases 2.626 g of Au from a gold salt is same as that which dissolves 1.26 g of Cu from copper anode during electrolysis of CuSO₄ solution. Oxidation number of gold in the gold salt is:

A cell contains two hydrogen electrodes. The negative electrode is in contact with a solution of 10^-6 M H⁺ ions. The emf of the cell is 0.118 V at 25⁰C. Concentration of H⁺ ion at the +ve electrode is 10^-xM. Value of x is:

In an electrolysis of an aqueous solution of NaOH, 2.8 L of oxygen gas at STP was liberated at anode. The volume of hydrogen gas at STP liberated at cathode is x times the volume of oxygen gas at anode value of x is:

A 0.05 N solution of a salt occupying a volume between two platinum electrode separated by a distance of 1.72 cm and having an area of 4.5 cm² has a resistance of 250 ohm. The equivalent conductance of the solution ( in ohm^–1 cm²) eq^–1, is:

For the cell reaction, at 25°C Mg|Mg²⁺_(aq)||Ag⁺_(aq)|Ag

maximum work that can be obtained by operating the cell is (in J)

Given: E°_mg²⁺/mg = –2.37 volt and E°_Ag⁺/_Ag = +0.80 volt:

The EMF of the concentration cell with transference, viz.,

Pt ; H₂ (1atm), HCl 

Is 0.028 V at 25°C. The EMF of the corresponding cell without transference is 0.017 V. The transference number of the H⁺ ion is:

 Emf of the cell (1 atm) | H⁺ (aq.) || AgCl|Ag is 0.27 V and 0.26 V at 25⁰C and 35⁰C. Heat of reaction occurring inside the cell at 25⁰C is.

While determining the pH of a solution, the quinhydrone electrode, H⁺ , Q. QH₂ was used in conjuction with a saturated calomel electrode, as represented below:

Hg, Hg₂Cl₂ (s) ; KCl (sat, soln.) || H⁺ (unknown); Q, QH₂, Pt

The EMF of the cell was found to be 0.26 volt at 25°C. Calculate the pH of the solution at this temperature. E_calomel = + 0.24 volt at 25°C and 

I_2(s)|I^–_(0.1m) half-cell is connnected to H⁺_(aq)|H_2(1atm) pt half-cell and its cell potential is found to be 0.7714 V. If the pH of H⁺/H₂ half-cell will be: