Assertion : `Na_(2)SO_(4)` is soluble in water while `BaSO_(4)` is water insoluble.
Reason :Lattice energy of `BaSO_(4)` exceeds its hydration energy.

Options

A. If both `(A)` and `(R )` are correct and `(R )` is the correct explanation of `(A)`
B. If both `(A)` and `(R )` are correct and `(R )` is the correct explanation of `(A)`
C. If `(A)` is correct but `(R )` is incorrect
D. If `(A)` is incorrect but `(R )` is correct

Answer

A

Explanation

For ionic compounds if lattice enthalpy `(Delta_(U)H^(theta))` gt Hydration enthalpy `(Delta_(hyd)H^(Theta))` the compound is insoluble and vice versa
For `Na_(2) SO_(4) : Delta_(U)H^(Theta) lt Delta_(hyd)H^(Theta)` thus it is soluble in `H_(2)O`
For `Ba SO_(4): Delta_(U)H^(Theta) gt Delta_(hyd) H^(Theta)` thus it is insoluble in `h_(2)O` .