CaO and NaCl has same crystal structure and same radius if lattice enthalpy of NaCl is U than the lattice enthalpy of CaO is ?

CaO and NaCl has same crystal structure and same radius if lattice ent

1.	CaO and NaCl has same crystal structure and same radius if lattice enthalpy of NaCl is U than the lattice enthalpy of CaO is ?
Answer» `(U)/(2)` U 2U 4U Solution :4U Lattice ENERGY = `(q_(1) q_(2))/(l^(2))` where `q_(1) and q_(2)` are charge l = distance between them . In CaO and NaCl ionic distance is same. In `Na^(+) and CL^(-) rarr` charge is 1 In `CA^(2+) and O^(2-) rarr ` charge is 2 So, lattice energy of CuO is 4 times than NaCl.