Question

How do the relative solubilities of these metals (Na, Li, Ca, K) compare to their relative

reactivities? Rank the reactivity of the Alkaline earth metals and compare that to solubility of

the hydroxides. Is there a correlation? What would you predict to be true about the solubility of

strontium hydroxide?

Briefly explain why.

Answer 1

The salt with more reactive ion attatched to it will be more soluble , because high reactivity means lower energy required to break the ionic bond between the two ions.

For example , if the salts are KOH and Ca (OH)_{2 ,} then KOH will be more soluble since K is more reactive than Ca.

The order of reactivity is Na>K>Na>Ca

In alkaline earth metals the reactivity increases from top to bottom so the solubility of alkaline earth metal hydoxides will be

Be(OH)₂ >Mg (OH)₂>Ca (OH)₂>Sr(OH)₂>Ba(OH)₂>Ra(OH)₂

Sr(OH)₂ is highly soluble in cold water , Since it has high reactivity compared to other alkali metals. It's preperation can be easily carried out by adding strong base such as NaOH or KOH drop by drop to any strontium salt .