What is the stock notation of Manganese dioxide?

A reaction, $$\mathrm{Ni}_{(\mathrm{s})}+\mathrm{Cu}_{(\mathrm{(M)})}^{+} \rightarrow \mathrm{Ni}_{(\mathrm{IM})}^{+}+\mathrm{Cu}_{(\mathrm{s})}$$ occurs in a cell. Calculate $$\mathrm{E}_{\text {cell }}^{\circ}$$ if $$\mathrm{E}_{\mathrm{Cu}}^{\circ}=0.337 \mathrm{~V}$$ and $$\mathrm{E}_{\mathrm{Ni}}^{\circ}=-0.257 \mathrm{~V}$$

What volume of ammonia is formed when $$10 ~\mathrm{dm}^3$$ dinitrogen reacts with $$30 ~\mathrm{dm}^3$$ dihydrogen at same temperature and pressure?

What is the number of moles of $$\mathrm{sp}^2$$ hybrid carbon atoms present in $$\mathrm{n}$$ moles of isopentane?