For the cell reaction,
Cu2+ (C1, aq) + Zn (s) Zn2+ (C2, aq) + Cu (s) of an electrochemical cell, the change in free energy (ΔG) at a given temperature is a function of
In (C1)
In (C2/ C1)
In (C2)
In (C1 + C2)
Standard reduction potentials at 25oC of Li+ / Li, Ba2+ / Ba, Na+ / Na and Mg2+ / Mg are -3.05, -2.90, -2.71 and -2.37 volt respectively. Which one of the following is the strongest oxidising agent?
Mg2+
Ba2+
Na+
Li+
On heating one end of a piece of a metal, the other end becomes hot because of
Energised electrons moving to the other end
Resistance of the metal
Mobility of atoms in the metal
Minor perturbation cell in the energy of atoms .
Equivalent conductance of NaCl, HCl and C2H5COONa at infinite dilution are 126.45, 426.16 and 91 ohm-1 cm2, respectively. The equivalent conductance of C2H5COOH is
201.28 ohm-1 cm2
390.71 ohm-1 cm2
698.28 ohm-1 cm2
540.48 ohm-1 cm2
In electrolysis of NaCl when Pt electrode is taken then H2 is liberated at cathode while with Hg cathode it forms sodium amalgam because
Hg is more inert than Pt
More voltage is required to reduce H+ at Hg than at Pt
Na is dissolved in Hg while it does not dissolve in Pt
Concentration of H+ ions is larger when Pt electrode is taken
Reduction potential for the following half-cell reactions are
+ 0.32 V
- 0.32 V
+ 1.20 V
- 1.20 V
The specific conductance of a 0.1 N KCl solution at 23o C is 0.012 ohm-1 cm-1. The resistance of cell containing the solution at the same temperature was found to be 55 ohm. The cell constant will be
0.142 cm-1
0.66 cm-1
0.918 cm-1
1.12 cm-1
A hypothetical electrochemical cell is shown below
A | A+ (xM) || B+ (yM) | B
The emf measured is + 0.20 V. The cell reaction is
A + B+ → A+ + B
A+ + B → A + B+
A+ + e- → A; B+ + e- → B
The cell reaction cannot be predicted
Which one of the following pairs of substances on reaction will not evolve H2 gas?
Iron and H2SO4 (aqueous)
Iron and Steam
Copper and HCl (aqueous)
Sodium and Ethyl alcohol
Without losing its concentration ZnCl2 solution cannot be kept in contact with
Au
Al
Pb
Ag