Question

At 80 degrees celcius ,15g of KCl and KCLO3 will dissolve in 100g of water. suppose yo mad e a solution containing 15g of KCl and 15g of KCLO3 in 100g of water and heated it to 80 degrees celcius.If you slowly cooled this solution to 0 degree celc`ius, explain what would happen.

Answer 1

the above graph show the solubility of inorganic compounds in 100gm of water at different Temperature.

From this graph it is seen that at 80'C the solubility of KCl and KCLO3 is aprox 52gm and 38 gm respectively, this means at 80'C in 100g water we can dissolve maximum 52gm of KCl and beyond this amount will not dissolve and will settle at the bottom of the container.

And at 0'C the solubility of KCl and KClO3 is 20gm( approximate value) and 3gm(aprox)

Now if the solution start to cooling slowly then crystallization occurs (crystallization is a process to separate solid from liquid by cooling). When it slowly reaches to 0'C then solubility of KClO3 became 3gm at this stage so 15-3=12gm of KCLO3 will form a crystal and we can able to see two different solid phase but there will be no crystallization of KCl because at 0'C it has a solubility of 20gm which is more that the amount we dissolve in water

So at 0'C only KClO3 will crystallize but KCl will not crystallize.