Identify the strongest reducing agent among alkali metals in aqueous solution and in the gaseous state, respectively.

Step-by-step solution

The reducing power of a metal is highly dependent on the medium in which the reaction occurs. In aqueous solution, reducing power is governed by the standard electrode potential, which is a combined effect of sublimation enthalpy, ionization enthalpy, and hydration enthalpy. Lithium ( Li ) has the most negative standard reduction potential due to its exceptionally high hydration enthalpy, which overcomes its high ionization enthalpy. Thus, Li is the strongest reducing agent in aqueous solution. In the gaseous state