\[CaO+{{H}_{2}}O\xrightarrow{\text{Hissing}\,\,\text{sound}}\]     \[Ca{{\left( OH \right)}_{2}}+\text{Heat}\]
\[CaO+C{{O}_{2}}\to CaC{{O}_{3}}\]

$$Ca$$  is obtained by electrolysis ofmolten mixture of $$CaC{l_2}$$  mixed with $$Ca{F_2}.$$

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$$N{a^ + }$$ and $$C{l^ - }$$ ions are free to move only in molten state or aqueous solution.

In Solvay ammonia process, sodium bicarbonate is precipitated due to common ion $$\left( {N{a^ + }} \right)$$  effect provided by brine ( concentrated $$NaCl$$  solution ).
$$N{H_4}HC{O_3} + NaCl + N{H_4}Cl$$       $$ + NaHC{O_3} \downarrow $$

$$\eqalign{ & NaHC{O_3} + NaOH \to N{a_2}C{O_3} + {H_2}O \cr & \left( {NaHC{O_3}\,{\text{is an acidic salt}}} \right) \cr} $$

On heating with excess of air $$Li,Na$$   and $$K$$  forms following oxides
\[\begin{align} & 4Li+{{O}_{2}}\to \underset{\text{Lithium monoxide }}{\mathop{2L{{i}_{2}}O}}\, \\ & 2Na+{{O}_{2}}\xrightarrow{575\,K}\underset{\text{Sodium peroxide }}{\mathop{N{{a}_{2}}{{O}_{2}}}}\, \\ & K+{{O}_{2}}\to \underset{\text{Potassium superoxide}}{\mathop{K{{O}_{2}}}}\, \\ \end{align}\]

$$Be{\left( {OH} \right)_2}$$  is least soluble in water hence, it will have lowest value of $${K_{sp}}.$$
$$Be{\left( {OH} \right)_2} \rightleftharpoons B{e^{2 + }} + 2O{H^ - };$$      $${K_{sp}} = \left[ {B{e^{2 + }}} \right]{\left[ {O{H^ - }} \right]^2}$$

Beryllium halides are essentially covalent and soluble in organic solvents like ethanol.

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