Which from following expressions is used to calculate $\mathrm{E}_{\text {cell }}$ for the following cell at $25^{\circ} \mathrm{C}$ ?

$$\mathrm{Pb}_{(\mathrm{s})}\left|\mathrm{Pb}_{(\mathrm{1M})}^{++} \| \mathrm{Ag}_{(\mathrm{10M})}^{+}\right| \mathrm{Ag}_{(\mathrm{s})}$$

Which of the following compounds is obtained by using Swartz reaction?

What is the bond order in CO molecule?

Which of the following is an example of heterogenous catalysis?