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2. s-Block Elements eLearn.Punjab
BeO(s) + H2SO4 (aq) → BeSO4 (s) + H2O(ï¬)
BeO(s) + 2NaOH(aq) → Na2BeO2 (aq) + H2O(ï¬)
Sodium beryllate
ii) Hydroxides
The alkali metal hydroxides are all crystalline solids, very
soluble in water except LiOH, which is slightly soluble. They are
generally hygrsocopic and are very strong bases, execpt LiOH.
The solubility of alkaline earth metal hydroxides in water increases
down the group. Be(OH)2 is quite insoluble. Mg(OH)2 is sparingly soluble
while Ba (OH)2 is more soluble. This increase in solubility is due to low
lattice energy of hydroxides which is, in turn, due to higher ionic size.
Alkali metal hydroxides are stable to heat except LiOH, while alkaline
earth metal hydroxides like Mg(OH)2 and Ca(OH)2 decompose on heating.
2LiOH(s) → Li2O(s) + H2O(ï¬)
Mg(OH)2 (s) → MgO(s) + H2O(ï¬)
A saturated solution of Ca(OH)2 in water is called lime water and is
used as a test for CO2. A suspension of Mg(OH)2 in water is called
milk of magnesia and it is used for treatment of acidity in stomach.
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