InterviewSolution
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InterviewSolution
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Discuss the trend of the following : (i) Thermal stability of carbonates of Group 2 elements . (ii) The solubility and the nature of oxides of Group 2 elements . |
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Answer» (ii) All alkaline earth metals react with `O_(2)` to form their respective oxides (MO) , their reactivity , however , increases down the group with increase in atomic size . Solubility in water . BeO being covalent is insoluble in water , MgO is only sparingly soluble in wate but all other oxides , i.e. , CaO , SrO and BaO dissolve in water with evolution of heat forming their corresponding hydroxides . `CaO + H_(2)O to Ca(OH)_(2) + ` heat The solubility of these oxides/hydration increase down the group because both the their lattice enthalpies and hydration enthalpies decrease down the group but their lattice enthalpies decrease more rapidly than their hydration enthalpies . Nature of oxides . Due to small size and somewhat high ionization enthalpy of Be, BeO is amphoteric and dissolves in both acids and alkalies . `BeO + 2HCl to BeCl_(2) + H_(2)O , BeO + 2 NaOH to underset("Sodium berrylate")(Na_(2)BeO_(2)) + H_(2)O` All other oxides are basic in nature and their basic character increases down the group . |
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