Which of the following changes occurs during the discharging of a lead accumulator?

Which of the following statements is correct? $A$ galvanic cell converts:

Which one of the following metals will not reduce $H_2O$?

Light can be converted into electricity with the help of a ......... .

In the electrochemical cell $H_{2(g)}, 1 \ atm \ | \ H^+_{(aq)}, 1 \ M \ || \ Cu^{2+}_{(aq)}, 1 \ M \ | \ Cu_{(s)}$,which of the following statements is true?

On the basis of the information available from the reaction $\frac{4}{3} Al + O_2 \to \frac{2}{3} Al_2O_3$,$\Delta G = -827 \ kJ \ mol^{-1}$ of $O_2$,the minimum emf required to carry out an electrolysis of $Al_2O_3$ is $............... \ V$