CBSE
Multiple Choice QuestionsAt 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 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
In Down's method for the extraction of sodium, the melting point of the electrolyte is lowered by adding
potassium chloride
calcium chloride
both calcium chloride and potassium fluoride
potassium fluoride only
Calcium is obtained by
electrolysis of molten CaCl2
electrolysis of solution of CaCl2 in water
reduction of CaCl2 with carbon
roasting of lime stone
What is the effect of dilution on the equivalent conductance of strong electrolyte?
Decrease on dilution
Remains unchanged
Increase on dilution
None of the above
Short Answer TypeA cell is represented by Zn|Zn2+ (aq) || Cu2+ (aq)| Cu. Given, Cu2+ + 2e- → Zn, E° = -0.763 V. Write the cell reactions, emf of the cell and state whether the cell reaction will be spontaneous or not?
Multiple Choice QuestionsCadmium rods are used for which purpese?
Emit electrons
Absorb neutrons
Emit neutrons
Absorb electrons
The potential of a hydrogen electrode at pH = 10 is
0.59 V
0.00 V
-0.59 V
- 0.059
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
A current of 12 ampere is passed through an electrolytic cell containing aqueous NiSO4 solution. Both Ni and H2 gas are formed at the cathode. The current efficiency is 60%. What is the mass of nickel deposited on the cathode per hour?
7.883g
3.941g
5.91g
2.645g
