Determine the equivalent weight of each given below, if formula weight of these compounds are `X,Y` and `Z` respectively:
(i) `Na_(2)SO_(4)`, (ii) `Na_(3)PO_(4). 12H_(2)O`
(iii) `Ca_(3)(PO_(4))_(2)`

Explanation

Equilibrium weight of compound
`= ("Molecular weight")/("Total charge on cartion or anion")`
`E_(Na_(2)SO_(4)) = (x)/(2)` (charge on `2Na` is `+2` or on `SO_(4) is -2)`
`E_(Na_(3)PO_(4).12H_(2)O) = (y)/(3)` , (charge on `PO_(4)` is `-3`)
`E_(Ca_(3)(PO_(4))_(2) = (z)/(6)` , (charge on `2PO_(4)` is `-6`)