An electrochemical cell is shown below
Pt, H2 (1 atm) |HCl (0.1 M)| CH3COOH(0.1 M)| H2 (1 atm), Pt. the emf of the cell will not be zero, because
emf depends on molarities of acids used
pH of 0.1 M HCl and 0.1 M CH3CHOOH is not same
The temperature is constant
Acids used in two compartments are different
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
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+
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
Cell reaction is spontaneous when
Eored is negative
Eored is positive
ΔGo is negative
ΔGo is positive
Cu+ (aq) is unstable in solution and undergoes simultaneous oxidation and reduction according to the reaction
2 Cu+ (aq) Cu2+ (aq) + Cu (s)
Choose the correct Eo for above reaction if
- 0.38 V
+ 0.49 V
+ 0.38 V
- 0.19 V
4.5 g of aluminium (at. mass 27 u) is deposited at cathode from Al3+ solution by a certain quantity of electric charge. The volume of hydrogen produced at STP from H+ ions in solution by the same quantity of electric charge will be
44.8 L
22.4 L
11.2 L
5.6 L
Without losing its concentration ZnCl2 solution cannot be kept in contact with
Au
Al
Pb
Ag
EoFe2+/Fe = -0.441 V and EoFe2+/Fe2+= 0.771V, the standard emf of the reaction Fe +2Fe3+ →3Fe 2+ will be
0.111 V
0.330 V
1.653 V
1.212 V
Al2O3 is reduced by electrolysis at low potentials and high currents. If 4.0 × 104 A of current is passed through molten Al2O3 for 6 hours, what mass of aluminium is produced? (Assume 100% current efficiency, at mass of Al = 27 g mol-1)
9.0 × 103 g
8.1 × 104 g
2.4 × 105 g
1.3 × 104 g