Which element from following has largest ionic size in +3 state?

Identify the principle suggesting to avoid protection and deprotection of selective group for organic reactions in green chemistry.

What is value of $E_{\text {cell }}$ at 298 K for the reaction, $\mathrm{Zn}_{(\mathrm{s})}+\mathrm{Cu}^{+2}(0.1 \mathrm{M}) \longrightarrow \mathrm{Zn}^{+2}(0.1 \mathrm{M})+\mathrm{Cu}_{(\mathrm{s})}$ if $\mathrm{E}_{\text {cell }}^{\circ}=1.1 \mathrm{~V}$ ?

Which of the following compounds has high lattice enthalpy?