Saturated solution of KNO3 is used to make 'salt-bridge' because:
1. velocity of K+ is greater than that of
2. velocity of is greater than that of K+
3. Velocities of both K+ and are nearly the same
4. KNO3 is highly soluble in water
A silver cup is plated with silver by passing 965 coulomb of electricity. The amount of Ag deposited is:
1. 1.08 g
2. 1.0002 g
3. 9.89 g
4. 107.89 g
At 25 °C molar conductance of 0.1 molar aqueous solution of ammonium hydroxide is 9.54 Ω-1 cm2 mol-1 and at infinite dilution its molar conductance is 238 Ω-1 cm2 mol-1. The degree of ionisation of ammonium hydroxide at the same concentration and temperature is :
1. | 2.080 % | 2. | 20.800 % |
3. | 4.008 % | 4. | 40.800 % |
When a copper wire is immersed in a solution of AgNO3, the colour of the solution becomes blue because copper:
1. Forms a soluble complex with \(AgNO_3\)
2. Is oxidised to \(Cu^{2+}\)
3. Is reduced to \(Cu^{2-}\)
4. Splits up into atomic form and dissolves
The specific conductance of a 0.1 M KCl solution at 23 °C is 0.012 Ω-1 cm-1 . The resistance of cells containing the solution at the same temperature was found to be 55 Ω. The cell constant will be:
1. | 0.142cm-1 | 2. | 0.66 cm-1 |
3. | 0.918 cm-1 | 4. | 1.12cm-1 |
Without losing it's concentration, ZnCl2 solution cannot be kept in contact with :
1. Au
2. Al
3. Pb
4. Ag
Al2O3 is reduced by electrolysis at low potentials and high currents. If 4.0 x 104 A of current is passed through molten Al2O3 for 6 h, what mass of aluminium is produced? (Assume 100% current efficiency, atomic mass of Al = 27g mol-1)
1. 9.0 x 103 g
2. 8.1 x 104 g
3. 2.4 x 105 g
4. 1.3 x 104 g
The standard reduction potential at 290 K for the following half reactions are,
(i) Zn2+ + 2e— → Zn(s); E° = -0.762 V
(ii) Cr3+ + 3e → Cr(s); E° = -0.740 V
(iii) 2H+ + 2e → H2(g); · E° = +0.000 V
(iv) Fe3+ + e → Fe2+; E° = +0.77V
Which is the strongest reducing agent?
1. Zn
2. Cr
3. Fe2+
4. H2
The Zn acts as sacrificial or cathodic protection to prevent rusting of iron because:
1. of Zn < of Fe
2. of Zn > of Fe
3. of Zn = of fe
4. Zn is cheaper than iron
What mass of copper will be deposited by passing 2 faraday of electricity through a solution of Cu(II) salt?
1. 35.6 g
2. 63.5 g
3. 6.35 g
4. 3.56 g
The same amount of electricity was passed through two cells containing molten Al2O3 and molten NaCl. If 1.8 g of Al were liberated in one cell, the amount of Na liberated in the other cell is:
1. 4.6 g
2. 2.3 g
3. 6.4 g
4. 3.2 g
Standard Reduction electrode potential of three metals X, Y, and Z are -1.2 V, +0.5 V and -3 V respectively. The reducing power of these metals will be :
1. | Y > X >Z | 2. | Z > X > Y |
3. | X > Y > Z | 4. | Y > Z > X |
During an electrolysis experiment, if a 100 mA current is passed through a solution of AgNO3 for 30 minutes, how many coulombs of electricity will be consumed?
1. 108 C
2. 18000 C
3. 180 C
4. 3000 C
Standard reduction potentials at 25C of Li+/Li, Ba2+/Ba, Na+/Na and Mg2+/Mg are -3.05, -2.90, -2.71 and -2.37 V respectively. Which one of the following is the strongest oxidising agent ?
1. Mg2+
2. Ba2+
3. Na+
4. Li+
For the cell, Ti|Ti+(0.001M)||Cu2+(0.1M)|Cu,Ecell at 25C is 0.83 V. Ecell can be increased:
1. By increasing [Cu2+]
2. By increasing [Ti+]
3. By decreasing [Cu2+]
4. None of these
A hydrogen gas electrode is made by dipping platinum wire in a solution of HCI of pH = 10 and by passing hydrogen gas around the platinum wire at 1 atm pressure. The oxidation potential of the electrode would be:
1. 0.059 V
2. 0.59 V
3. 00.118 V
4. 1.18 V
The atomic mass of Al is 27. When a current of 5 faraday is passed through a solution of Al3+ ions, the mass of Al deposited is:
1. 27 g
2. 36 g
3. 45 g
4. 9 g
On the basis of the information available from the reaction.
of O2, the minimum EMF required to carry out the electrolysis of Al2O3 is : (F=96500 C mol-1)
1. 2.14 V
2. 4.28 V
3. 6.42 V
4. 8.56 V
For the reductidon of silver ions with copper metal, the standard cell potential was found to be + 0.46 V at 250C. The value of standard Gibbs energy(ΔG0) will be ;
(F = 96500 Cmol-1)
1. -89.0 KJ
2. -89.0 J
3. -44.5 KJ
4. -98.0 KJ
A solution of sodium sulphate in water is electrolysed using inert electrodes. The products at the cathode and anode are respectively:
1. H2, O2
2. O2, H2
3. O2, Na
4. O2, SO2
If a salt bridge is removed from the two half cells, the voltage:
1. Drops to zero.
2. Does not change.
3. Increases gradually.
4. Increases rapidly.
Two electrolytic cells, one containing acidified ferrous chloride and another acidified ferric chloride are connected in series. The ratio of iron deposited at cathodes in the two cells when electricity is passed through the cells will be:
1. 3:1
2. 2:1
3. 1:1
4. 3:2
Pick out the incorrect statement
1. Equivalent conductance increases with dilution
2. Molar conductance increases with dilution
3. Specific conductance increases with dilution
4. Specific resistance increases with dilution
The cell potential for this reaction is 0.46V. Which of the following change will increase the potential the most ?
(1) concentration is doubled
(2) [Cu2+] concentration is halved
(3) Size of Cu(s) electrode is doubled
(4) size of Ag(s) electrode is decreased to half
What will be the value of for the rection
if
(1) -65.62 KJ
(2) -75.27 KJ
(3) -150.54 KJ
(4) +150.54 KJ
The cell reaction of micro electrochemical cell formed during rusting of iron is:-
1.
2.
3.
4.
For the cell reaction
the change in free energy at a given temperature is a function of
(1) lnC1
(2) ln
(3) ln (C1 +C2)
(4) lnC2
the emf of Voltaic cell
(1) 1.25 V
(2) -1.75 V
(3) 1.75 V
(4) 4 V
The same amount of electric current is apassed through aqueous solution of MgSO4 and AlCl3. If 2.8 g Mg metal is deposited at amount of Al metal deposited in second cell will be
1. 2.1 g
2. 2.49 g
3. 3.15 g
4. 3.73g
A device that converts energy of the combustion of fuels like hydrogen and methane, directly
into electrical energy is known as:
1. Fuel cell
2. Electrolytic cell
3. Dynamo
4. Ni-Cd cell
gas can’t be obtained by the electrolysis of any salt because-
1. Fluorine is the strongest reducing agent
2. Fluorine is the strongest oxidising agent.
3. Fluorine easily combine with atmospheric
4. All
If the E°cell for a given reaction has a negative value then which of the following gives the
correct relationships for the values of G° and Keq?
1. G° < 0;Keq > 1
2. G° < 0; Keq < 1
3. G°> 0; Keq < 1
4. G° > 0; Keq > 1
Acetic acid has Ka = 1.8 × 10–5 while formic acid had Ka = 2.1 × 10–4. What would be the magnitude of the emf of the cell
Pt(H2) Pt(H2) at 25°C
(1) 0.0315 volt
(2) 0.0629 volt
(3) 0.0455 volt
(4) 0.0545 volt
During discharge of a lead storage cell the density of sulphuric acid in the cell-
(A) Increases
(B) Decreases
(C) Remains unchanged
(D) Initially increases but decreases subsequently
What will be the quantity of iron deposited by ferrous and ferric ion by 1F (Fe = 56)
(1) 14g, 9.3 g
(2) 28g, 18.6 g
(3) 56g, 37.2g
(4) None of these
Specific conductance has the unit:
1.
2. ohm.cm
3.
4.
What is the value of if for 0.04 of a at ?
(A) 9.3
(B) 9.2
(C) 4.7
(D) 4.8
A certain current liberates 0.504 g of hydrogen in 2 hours. How many gram of copper can be liberated by the same current flowing for the same time in aqueous solution :
(1) 12.7
(2) 16
(3) 31.8
(4) 63.5
The metal that cannot be produced on reduction of its oxide by aluminium is :
(1) K
(2) Mn
(3) Cr
(4) Fe
The given cell reaction is:
1. Feasible
2. Not feasible
3. In equilibrium
4. None of the above
Adiponitrile is manufactured electrolytically from acrylonitrile
How many kg of adiponitrile (molecular mass = 108) is produced in 9.65 hr using a current of 3750 A with 80% efficiency?
(1) 30 kg
(2) 58 kg
(3) 60 kg
(4) 80 kg
A certain metal salt solutions is electrolysed in series with a silver coulometer. The weights of silver and the metal deposited are 0.5094 g and 0.2653 g. Calculate the valency of the metal if its atomic weight is nearly that of silver.
(1) 1
(2) 2
(3) 3
(4) 4
1Ag has emf, . The 2lectrode potential for the reaction AgI + is -0.151 volt. Calculate the pH 3alue.
(1) 3.37
(2) 5.26
(3) 2.56
(4) 4.62
The temperature coefficient of a standard Cd-cell is whose emf at is 1.018 V. During the cell operation, the temperature will -
(1) increase
(2) decreases
(3) either
(4) remains constant
Calculate the useful work of the reaction \(Ag(s) + {1 \over 2} Cl_2(g) \rightarrow AgCl(s)\)
(1) 110 kJ/mol
(2) 220 kJ/mol
(3) 55 kJ/mol
(4) 1000 kJ/mol