Lithium is often used as the negative pole in ‘button’ cells used to power watches.

a. Explain why lithium is often used to make electrochemical cells.

b. The half-equations for a lithium/iodine button cell are:

Li⁺ + e^– ⇌ Li                          E^θ= –3.04 V

1/2 I₂(s) + e^– ⇌ I^–(aq)           E^θ= +0.54 V

i. Predict the cell voltage of this cell using the E^θvalues for the two half-equations above.

ii. The actual voltage of a lithium/iodine button cell is 2.8 V. Suggest why this is different from the value you calculated in part i.

c. Give two advantages of a lithium/iodine cell compared with an ordinary dry cell.