Percentage composition of a salt is K=8.23%, Al=5.70%, `SO_(4)=40.51% and H_(2)O=45.5%`. What is the empirical formula of the compound? The molecular mass of the compound is 948. what is its molecular formula?

Explanation

In the compound ratio of K, Al `SO_(4)^(2-)` radicals and `H_(2)O`
`K:Al:SO_(4):H_(2)O=(8.23)/(39):(5.7)/(27):(40.51)/(96):(45.5)/(18)`
`=0.211:0.211:0.422:2.527=1:1:2:12`
`therefore`Empirical formula of the compound
`[Kal(SO_(4))_(2)(H_(2)O)_(12)]` and molecular formula:
`[KAl(SO_(4))_(2)(H_(2)O)_(12)]_(x)`

`therefore` Molecular mass
`=[39+27+3xx96+12xx18]xx x=57xx x`
As given in the question `570xx x=948" "thereforex~~2`
`therefore`Molecular formula of the compound :
'K2Al2(SO4)2(H2O)24'.