How do the alkali metals differ from the alkaline earth metals? a. alkali metals are much less reactive than alkaline earth metals. b. alkali metals are much harder than the alkaline earth metals. c. alkali metals exist in pure form; alkaline earth metals appear in nature as compounds. d. alkali metals have one valence electron and alkaline earth metals have two.

)benzene and toluene form nearly ideal solutions. consider an equimolar solution of benzene and toluene. at 20 °c the vapour pressures of pure benzene and toluene are 9.9 kpa and 2.9 kpa, respectively. the solution is boiled by reducing the external pressure below the vapour pressure. calculate (i) the pressure when boiling begins, (ii) the composition of each component in the vapour, and (iii) the vapour pressure when only a few drops of liquid remain. assume that the rate of vaporization is low enough for the temperature to remain constant at 20 °c.