Li occupies a higher position in the electrochemical series of metals as compared to Cu since :
the standard reduction potential of Li+/Li is lower than that of Cu2+/Cu
the standard reduction potential of Cu2+/Cu is lower than that of Li+/Li
the standard oxidation potential of Li+/Li is lower than that of Cu2+/Cu
Li is smaller in size as compared to Cu
A hydrogen gas electrode is made by dipping platinum wire in a solution of HCl of pH=10 and by passing hydrogen gas around the platinum wire at 1 atm pressure. The oxidation potential of electrode would be
0.059 V
0.59 V
0.118V
1.18V
At 25°C molar conductance of 0.1 molar aqueous solution of ammonium hydroxide is 9.54 ohm-1cm2 mol-1 and at infinite dilution its molar conductance is 238 ohm-1cm2 mol-1. The degree of ionisation of ammonium hydroxide at the same concentration and temperature is
2.080%
20.800%
4.008%
40.800%
The quantity of electricity needed to separately electrolyze 1 M solution of ZnSO4 , AlCl3 and AgNO3 completely is in the ratio of
2 : 3 : 1
2 : 1 : 1
2 : 1 : 3
2 : 2 : 1
On passing C ampere of current for the time 't' sec through 1 L of 2 (M) CuSO4 solution (atomic weight of Cu= 63. 5), the amount 'm' of Cu (in gram) deposited on cathode will be
m = Ct/(63.5 x 96500)
m = Ct/(31.25 X 96500)
m = (C x 96500)/(31.25 x t)
m = (31.25 X C x t)/96500
The two half-cell reactions of an electrochemical cell is given as
Ag+ + e- → Ag; = -0.3995 V
Fe2+ → Fe3+ + e- ; = -0.7120 V
The value of cell EMF will be
-0.3125 V
0.3125 V
1.114 V
-1.114 V
At 25°C, the molar conductance of 0.007 M hydrofluoric acid is 150 mho cm2mol-1 and its Λ°m = 500 cm2mol-1. The value of the dissociation constant of the acid at the given concentration at 25°C is
7 × 10-4 M
7 × 10-5 M
9 × 10-3 M
9 × 10-4 M
The standard reduction potential Eo for half-reaction are:
Zn Zn2+ + 2e- ; E° = + 0.76V
Fe Fe2+ + 2e- ; E° = + 0.41 V
The EMF of the cell reaction
Fe2+ + Zn Zn2+ + Fe is :
- 0.35 V
+ 0.35 V
+ 1.17 V
- 1.17 V
The formal potential of Fe3+ /Fe2+ in a sulphuric acid and phosphoric acid mixture (E° = +0.61 V) is much lower than the standard potential (E° = +0.77 V). This is due to
formation of the species [FeHPO4]+
lowering of potential upon complexation
formation of the species [FesO4]+
high acidity of the medium