Answer:
1. KNO3(s) ------> K^+(aq) + NO3^-(aq)
2. The dissolution is endothermic
3. The sign of the enthalpy of dissolution is positive
Step-by-step explanation:
The sign of the enthalpy of dissolution depends on the hydration energy and the lattice energy.
For KNO3, the hydration energy is less than the lattice energy hence the dissolution is endothermic and the enthalpy of dissolution is positive.