I encountered a problem which required me to compare the solubility of $\ce{AlF3}$ in various solvents, namely $\ce{HF}$, $\ce{KF}$ & $\ce{KHF2}$ .

Further, this problem neither supplied, nor expected me to utilize any solubility data. Infact, the problem only asked for the expected order, discounting any exceptional factors that may affect the actual numerical data.

My thoughts regarding this are as follows;

  1. As $\ce{AlF3}$ is a Lewis acid, I expect it to have higher solubility in solvents which have lone pair containing donor ; possibly the fluoride ion from $\ce{KF}$ may be such a species
  2. Further, in aqueous acidic solution, I expect a lower solubilty owing to common ion effect lowering the solubility
  3. I am unsure and unclear regarding the action of $\ce{KHF2}$
  4. Perceptions regarding H-bonding and complex formations also seem to apply, but I am unable to formulate these coherently

Given these points, can someone help me to organize my thoughts? I wish to know the lines along which I should guide my thoughts.

  • $\begingroup$ The Handbook of Chemistry and Physics mentions that $\ce{AlF3}$ is soluble in water, and that $\ce{AlF3·3H2O}$ is not soluble in water. So it is difficult to say if any of these substances will be soluble in $\ce{ KF, KHF2}$ or $\ce{HF}$. $\endgroup$
    – Maurice
    Jan 16 at 17:11
  • 2
    $\begingroup$ See: chemistry.stackexchange.com/questions/65861/… $\endgroup$ Jan 17 at 4:33
  • $\begingroup$ @NilayGhosh thanks for the link to that question ; the answers over there answer my query. $\endgroup$
    – user95829
    Jan 17 at 8:48

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