(a). Na_(2)SO_(4) is soluble in water whereas BaSO_(4) is insoluble. Why? (b). When Mg metal is burant in air, a white powder is left behind as ash. What is the white powder?

(a). Na_(2)SO_(4) is soluble in water whereas BaSO_(4) is insoluble. W

1.	(a). Na_(2)SO_(4) is soluble in water whereas BaSO_(4) is insoluble. Why? (b). When Mg metal is burant in air, a white powder is left behind as ash. What is the white powder?
Answer» Solution :a. The lattice enthalpy of `Na_(2)SO_(4)` is less than its hydration enthalpy whereas the lattice enthalpy of `BaSO_(4)` (because of `+2` charge of `ba^(2+))` is very higa as compared to its hydraton enthalpy. That is why `Na_(2)SO_(4)` is soluble in water whereas `BaSO_(4)` is INSOLUBLE. b. Magnesium on burning in air REACTS with oxygen and nitrogen resulting in the FORMATION of `MGO` and `Mg_(3)N_(2)`. `2 Mg+O_(2)rarr2MgO` `3 Mg+N_(2)rarrMg_(3)N_(2)` White powder is the mixure of `MgO` and `Mg_(3)N_(2)`.