Passage of three faradays of charge through an aqueous solution of AgNO3, CuSO4, Al(NO3)3, and NaCl will deposit moles of metals at the cathode in the molar ratio of:
1. | 1 : 2 : 3 : 1 | 2. | 6 : 3 : 2 : 6 |
3. | 6 : 3 : 0 : 0 | 4. | 3 : 2 : 1 : 0 |
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 |
A solution containing one mole per litre each of Cu(NO3)2, AgNO3, Hg2(NO3)2 and Mg(NO3)2 is being electrolyzed by using inert electrodes. The values of standard electrode potentials in volt (reduction potentials) are,
Ag+ /Ag = 0.80 V, /2Hg = 0.79 V,
Cu2+/Cu = +0.34 V and Mg2+/Mg = -2.37 V
With increasing voltage, the sequence of deposition of metals on the cathode will be:
1. Ag, Hg, Cu, Mg
2. Mg, Cu, Hg, Ag
3. Ag, Hg, Cu
4. Cu, Hg, Ag
The change in reduction potential of a hydrogen electrode when its solution initialy at pH = 0 is neutralised to pH = 7, is a/an-
1. | Increase by 0.059 V | 2. | Decrease by 0.059 V |
3. | Increase by 0.41 V | 4. | Decrease by 0.41 V |
When a lead storage battery is discharged, then:
1. SO2 is evolved.
2. Lead is formed.
3. Lead sulphate is consumed.
4. Sulphuric acid is consumed.
A depolariser used in dry cell batteries is:
1. Ammonium chloride
2. Manganese dioxide
3. Potassium hydroxide
4. Sodium phosphate
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.
The standard reduction potential for Fe2+|Fe and Sn2+|Sn electrodes are -0.44 V and -0.14 V respectively. For the cell reaction,
Fe2+ + Sn → Fe + Sn2+, the standard Emf is -
1. +0.30 V
2. 0.58 V
3. +0.58 V
4. -0.30 V
Without losing it's concentration, ZnCl2 solution cannot be kept in contact with :
1. Au
2. Al
3. Pb
4. Ag
If an iron rod is dipped in CuSO4 solution, then:
1. Blue colour of the solution turns red.
2. Brown layer is deposited on iron rod.
3. No change occurs in the colour of the solution.
4. None of the above.