Which metal oxide decomposes upon heating?

Which of the following is $NOT$ an example of a secondary voltaic cell?

Select the false statement from the following regarding an electrochemical cell.

At $298 \ K$ temperature,if $E^o_{Mg^{2+}|Mg} = -2.37 \ V$ and $E^o_{Co^{2+}|Co} = -0.28 \ V$,construct a galvanic cell and provide its symbolic representation.

For the cell $Cu_{(s)} | Cu^{2+}_{(aq)} (1 \ M) || Zn^{2+}_{(aq)} (1 \ M) | Zn_{(s)}$,given $E^{\circ}_{Zn^{2+}/Zn} = -0.76 \ V$ and $E^{\circ}_{Cu^{2+}/Cu} = 0.34 \ V$,the cell reaction is:

Which of the following is an incorrect statement?