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
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.
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
The efficiency of a fuel cell is given by:
1.
2.
3.
4.
The correct statement about charging of the lead storage battery is:
1. PbSO4 anode is reduced to Pb.
2. PbSO4 cathode is reduced to Pb.
3. PbSO4 cathode is oxidised to Pb.
4. PbSO4 anode is oxidised to PbO2.
In a typical fuel cell, the reactants (R) and products (P) are:
1. | R = H2(g), O2(g); P = H2O2(l) |
2. | R = H2(g), O2(g); P = H2O(l) |
3. | R = H2(g) , O2(g) , C l2(g) ; P = HClO4(aq) |
4. | R = H2(g) , N2(g) ; P = NH3(aq) |
Rusting of iron is envisaged as setting up of an electrochemical cell because:
1. Oxidation of iron takes place during rusting.
2. Reduction of iron takes place.
3. Iron shows disproportionation reaction.
4. Oxygen is getting oxidised.