Which of the following elements has the highest reaction rate with water?

$Mg$ is obtained by:

The correct order of hydration enthalpies of alkali metal ions is

The atomic radii of alkali metals $(M)$ lie in the order $Li < Na < K < Rb$,but the radii of $M^{+}$ ions in aqueous solution lie in the reverse order $Li^{+} > Na^{+} > K^{+} > Rb^{+}$. What is the reason for this reverse order (on going from $Li$ to $Rb$)?

Which of the following statements is correct regarding alkali metals?

Which factor makes $Li$ the strongest reducing agent in aqueous solution?