A device that converts the energy of combustion of fuels, like hydrogen and methane, directly into electrical energy is known as: 

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 efficiency of a fuel cell is given by:

1. $\frac{∆H}{∆G}$

2. $\frac{∆G}{∆S}$

3. $\frac{∆G}{∆H}$

4. $\frac{∆S}{∆G}$

If hydrogen electrodes dipped in two solutions of pH = 4 and pH = 6 are connected by a salt bridge, the emf of the resulting cell is -

1. 0.177 V               

2. 0.3 V               

3. 0.118 V             

4. 0.104 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

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.