A button cell used in watches functions as following

The cell potential will be

• 1.10 V

• 0.42 V

• 0.84 V

• 1.34 V

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

• fuel cell

• electrolytic cell

• dynamo

• Ni-Cd cell

A hypothetical electrochemical cell is shown below
A^- | A⁺ (xM)|| B⁺ (yM)|B⁺

The emf measured is +0.20 V. The cell reaction is:

• A⁺ + B  →  A + B⁺

• A⁺ + e^-  →  A ; B⁺ + e^-  → B^-

• the cell reaction cannot be predicted

•  A⁺ + B  →  A⁺ + B

A solution contains Fe²⁺ Fe³⁺, and I^- ions. This solution was treated with iodine at 35^o C.E^o for Fe³⁺/ Fe²⁺ is +0.77 V and E^o for I₂/ 2 I^- = 0.536 V. The favourable redox reaction is 

• I₂ will be reduced to I^-

• There will be No redox reaction

• I^- will be oxidised to I₂

• Fe²⁺ will be oxidised to Fe³⁺

Al₂O₃ is reduced by electrolysis at low potentials and high currents. If 4.5 x 10⁴ An of current is passed through molten Al₂O₃ for 6h, what mass of aluminium is produced? (Assume 100% current efficiency, at.mass of Al = 27 g mol^-1)

• 9.0 x 10³ g

• 8.1 x 10⁴ g

• 2.4 x 10⁵ g 

• 1.3 x 10⁴ g