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A crystalline hydrated sa,t on being ren...

`A` crystalline hydrated sa,t on being rendered anhydrous, loses `45.6%` of its weight. The precentage composition of anhydrous salt is `:Al=10.5%, K=15.1%, S=24.8%` and `I=49.6%`. Find the empirical formula of the anhydrous and crystalline salt :

Text Solution

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The correct Answer is:
`KAIS_(2)O_(8),KAIS_(2)O_(8).12H_(2)O`
Empirical formula
`KAlS_(2)O_(8){{:(Al,K,S,O,"Elements",),(10.5,15.1,24.8,49.6,"Mass percentage",),(0.388,0.387,0.775,3.1,"Mole ratio",),(1,1,2,8,"Simple ratio",):}`
Empirical formula weight `= 258`
From weight loss information `:54.4 g` anhydrous
salt `-= 45.6 g H_(2)O`
` implies 258g` anhydrous salt `-=216.26 g = 12` mol `H_(2)O`
implies Empirical formula of hydrated salt `=KAlS_(2)O_(8).12H_(2)O`
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