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    Group 2 compound's solubility increases down the group. Why is this so ? It says it releases more OH- ions but that doesn't exactly explain why. Can someone tell me the actually reason solubility increases down group 2?
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    (Original post by Questioness)
    Group 2 compound's solubility increases down the group. Why is this so ? It says it releases more OH- ions but that doesn't exactly explain why. Can someone tell me the actually reason solubility increases down group 2?
    As you go down the group for group 2 hydroxides the enthalpy of hydration becomes more negative as more favourable interactions are formed with water molecules. The opposite is true for the sulfates.

    In general, the bigger the mismatch in size between the cation and the anion, the greater its hydration enthalpy change and the more soluble the compound is in water. Sulfate is a fairly large cation and is bigger than group 2 metal cations. As you go down the group, the ionic radius of the cation is getting larger and more similar to that of the sulfate ion. The opposite is true for the hydroxides as the hydroxide anion is smaller than the metal cations and becomes less similar in size to the metals as you go down the group


    ^^ i don't really understand this but i found this answer on one of the TSR threads made years ago
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    Yea, Actually I don't quiet get it either. Maybe my questions requires a little more complicated answer than I anticipated.
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    (Original post by thefatone)
    As you go down the group for group 2 hydroxides the enthalpy of hydration becomes more negative as more favourable interactions are formed with water molecules. The opposite is true for the sulfates.

    In general, the bigger the mismatch in size between the cation and the anion, the greater its hydration enthalpy change and the more soluble the compound is in water. Sulfate is a fairly large cation and is bigger than group 2 metal cations. As you go down the group, the ionic radius of the cation is getting larger and more similar to that of the sulfate ion. The opposite is true for the hydroxides as the hydroxide anion is smaller than the metal cations and becomes less similar in size to the metals as you go down the group


    ^^ i don't really understand this but i found this answer on one of the TSR threads made years ago
    (Original post by Questioness)
    Yea, Actually I don't quiet get it either. Maybe my questions requires a little more complicated answer than I anticipated.
    You'll get to cover hydration and solution enthalpies at A2. I don't think you need to know the reason for this particular trend.
 
 
 
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