Which is the correct increasing order of atomic radii of $\mathrm{Na}, \mathrm{K}, \mathrm{Mg}, \mathrm{Rb}$ ?

Identify the element having highest ionisation enthalpy ( $I E_1$ ) from following.

Identify the reagent used in the following reaction.

Benzoic acid $\xrightarrow{\text { Reagent }}$ Benzoyl chloride + Phosphorus oxychloride + Hydrogen chloride

If $\mathrm{E}^o{}\left(\mathrm{AI}_{(\mathrm{eq})}^{+3} \mid \mathrm{AI}_{(\mathrm{s})}\right)=-1.66 \mathrm{~V}$. What is potential of $\mathrm{Al}_{(\mathrm{s})} \longrightarrow \mathrm{Al}^{+3}(0 \cdot 1 \mathrm{M})+3 \mathrm{e}^{-}$at 298 K ?