How does Le Chatelier's principle explain the result you obtained when you add HCL to a suspension of Ca(OH)2 in water? Where the result was, precipitate dissappeared and an increase in temperature resulted.

Answer 1

Ca(OH)2 solid in H2O. Saturated solution.
Ca(OH)2 + 2HCl ==> CaCl2 + H2O
Ca(OH)2 suspension. Saturated solution. Add HCl. The New ionic rxn is
2OH^- + 2H^+ ==> 2H2O. H2O is very weak electrolyte. Rxn goes to completion forming H2O. That reduces the OH^- in solution forcing more of the solid to dissolve. More HCl does the same thing; eventually all of the lime has dissolved. The temperature increases because H^+ + OH^- ==> H2O + heat; i.e., an exothermic reaction.