For `NaCl`, lattice energy ` = - 186 kcal//mol`, the solvation energy of `Na^(+) and Cl` are `-97 and -85 kcal//"mole"` respectively. Therefore for `NaCl (s)`

Options

A. enthalpy of solution is exothermic and magnitude equal to `4 kcal//mol`
B. enthalpy of solution is exothermic and magnitude equal to `4368 kcal//mol`
C. enthalpy of solution is endothermic and magnitude equal to `4 kcal//mol`
D. enthalpy of solution is endothermic and magnitude equal to `368 kcal//mol`

Answer

C

Explanation

Lattice energy for Breaking energy is `+ 186` kcal/mol `DeltaH_(solve) = - 97 - 85 = - 182 kcal//mol`
`-LE = + 186 kcal//mol`
`Delta H ("solution") = + 186 - 182 = 4 kcal//mol` & endothermic